Antibiotic-resistant genes (ARGs) have been regarded as emerging contaminants that threaten public health worldwide. Poultry excreta, often used as a fertilizer in agriculture, are a major route for the proliferation and dissemination of ARGs in the environment. The aim of the present study was to assess the potential of dietary palygorskite (Plg) supplementation as nutritional manipulation for the modulation of microbial community structure and the attenuation of ARGs in the cecal contents of broilers fed with chlortetracycline (CTC). In total, 256 one-day-old, mixed-sex, broiler chicks were allocated randomly into a 2 × 2 factorial design of four treatments, which consisted of two levels of CTC (0 or 50 mg/kg) and Plg (0 or 10 g/kg). By employing in vivo feeding and slaughter experiments, after collecting the cecal contents and extracting the total genomic DNA, 16S rRNA V3-V4 hypervariable amplicon pyrosequencing and quantitative PCR-based approaches were used to address the impact of Plg on microbiota and the abundance of ARGs in broilers. The results showed that broilers given a diet supplemented with Plg had greater α-diversity indices including Chao1, phylogenetic diversity tree, and observed-species index calculations, when compared with those without Plg supplementation. Birds given a diet supplemented with Plg had fewer Firmicutes at the phylum level, but a greater abundance of Alistipes at the bacterial genus level. Dietary Plg counteracted the CTC-induced increased abundance of ARGs, among which tet(K) had a pronounced decrease, along with a similar decreased tendency for other measured ARGs and intI1. Overall, the results indicated that Plg supplementation caused pronounced changes in cecal microbial diversity and microbiota community composition of broilers, and effectively reduced ARGs, indicating that Plg supplementation is a potential alternative measure for the attenuation of ARGs in the cecal contents of broilers.

Zearalenone (ZEA), a common contaminant in food and feedstuffs, threatens human and animal health. The present study aimed to investigate the protective effects of modified palygorskite (MPal), a ZEA-targeted adsorbent, on broilers (young chickens) fed a ZEA-contaminated diet. Broilers were subjected to one of three treatments for a period of 42 days: a basal diet (control group), a ZEA- contaminated diet, and a ZEA-contaminated diet supplemented with 1 g/kg of MPal. Blood was collected for serum metabolite assay, and liver and kidney were sampled to determine ZEA residue and antioxidant-related parameters, using commercial spectrophotometric kits. Compared with the basal diet, the ZEA- contaminated diet resulted in compromised growth performance (reduced daily gain and feed intake during finisher period), disordered relative liver weight (decreased at 21 days but increased at 42 days), increased ZEA residue in liver and kidney, abnormal serum metabolites (decreased total protein content but increased alanine aminotransferase activity at 21 and 42 days, reduced albumin content at 21 days, and elevated aspartate aminotransferase activity at 42 days), and disrupted antioxidant capacities of broilers (increased total superoxide dismutase (T-SOD) activity in liver at 21 and 42 days, decreased T-SOD activity in kidney at 21 and 42 days, and in serum at 42 days, greater malondialdehyde accumulation in liver and kidney at 42 days, and lower glutathione content in kidney at 21 days). The adverse consequences resulting from the ZEA-contaminated diet were relieved by the supplementation of MPal (except albumin concentration in serum and T-SOD activity in liver at 21 days), with the values of growth-performance parameters, liver weight, renal ZEA accumulation, total protein content, transaminase activity at 42 days, and antioxidant indexes being similar to those in the control group. These results suggested that MPal supplementation could promote growth performance, attenuate liver damage, and improve the antioxidant abilities of broilers fed ZEA-contaminated diet by reducing ZEA accumulation.

Controlled atmosphere (gas) stunning (CAS) has the potential to improve the welfare of poultry at slaughter but there is a lack of consensus about which gas mixtures are most humane. The aim of this study was to evaluate the welfare consequences of different gas stunning approaches. Individual broilers were exposed to gas mixtures capable of inducing unconsciousness and euthanasia while their behavioural, cardiac, respiratory and neurophysiological responses were measured simultaneously. The approaches investigated included anoxia (N2 or Ar with < 2% residual O2), hypercapnic anoxia (30% CO2 in Ar, 40% CO2 in N2) and a biphasic method (40% CO2, 30% O2, 30% N2 for 60 s followed by 80% CO2 in air). Evaluation of the welfare implications of each approach centred on the likelihood of them inducing negative states or experiences during the conscious phase. Hypercapnic mixtures were associated with strong respiratory responses, while anoxic mixtures induced vigorous wing flapping. Electroencephalogram analysis using the correlation dimension (a non-linear measure of complexity) suggested that anoxic wing flapping occurred during periods in which a form of consciousness could not be excluded. Hypercapnic hyperoxygenation (biphasic approach) exacerbated respiratory responses but eliminated the possibility of vigorous behavioural responses occurring during a conscious phase. The relative importance of respiratory discomfort versus the potential to induce significant distress due to convulsive wing flapping and associated trauma is a matter for debate. We argue that respiratory discomfort is unpleasant but may be preferable to the risk of vigorous wing flapping and associated injury while conscious in poultry during CAS.

The preferences of broiler and layer strains of fowl for four different intensities of incandescent luminaire (6, 20, 60 and 200 lux; Osram, 60W, pearl) were tested at 2 and 6 weeks of age. With each strain, four replicates of 12 birds were each allowed to move freely between four compartments illuminated continuously at the different intensities for 6 days. The distribution of light intensities among the compartments was changed daily. After 2 days of conditioning, the birds’ location and behaviour were recorded once every 15min over 23h on each of the remaining 4 days. The other hour was devoted to changing light intensities and refilling the feeders and drinkers. Six, mutually exclusive behaviours were defined: resting, perching, feeding, drinking, litter-directed activity and locomotion.

With both strains, most time was spent in the brightest (200 lux) environment at 2 weeks of age. but in the dimmest (6 lux) at 6 weeks. This apparent change in preference was associated only with the two behaviours which took up most time, resting and perching, whereas the highest intensity was consistently preferred for all other behaviours. Older birds thus preferred to be in dim light when they were relatively inactive.

The finding that older birds prefer to spend much of their time in a light environment of < 10 lux intensity, depending on behaviour, is contrary to current recommendations that minimum light intensities for broilers and laying hens should be increased to as much as 20 lux. Some variation in the spatial or temporal distribution of ambient light intensity, to provide both dimly (< 10 lux) and brightly (eg > 50 lux) lit environments, might benefit the welfare of older poultry, although further work is needed to establish their optimal light environment.

In Denmark and Sweden, surveys were undertaken to estimate the prevalence of leg problems in conventional broiler production. The Danish survey included 28 Ross 208 flocks, and the Swedish survey included 15 Ross 208 and 16 Cobb flocks. Leg problems included reduced walking ability (gait), tibial dyschondroplasia (TD), varus/valgus deformations (VV) and foot-pad dermatitis (FPD). Danish Ross chicks showed a significantly higher prevalence of gait score > 0, gait score > 2 and TD, but a lower prevalence of VV, than Swedish Ross chicks. Cobb chicks showed a significantly higher prevalence of gait score > 0, gait score > 2 and TD than Swedish Ross chicks, a significantly higher prevalence of VV than Danish Ross chicks, and a significantly lower prevalence of FPD than both Danish and Swedish Ross chicks. The two genotypes of Swedish chicks showed similar relationships between body weight and probability of gait score > 0, TD and VV, indicating that the difference in prevalence of these leg problems may be due to the difference in mean body weight at slaughter age. At body weights below 2300 g, Danish chicks showed a higher probability of gait score > 2 than Swedish chicks. Furthermore, at body weights below 1900 g, Danish chicks had a higher probability of TD than Swedish chicks, whereas at body weights above 2200 g they had a lower probability of TD. This indicates that the difference in prevalence of TD between Danish and Swedish chicks was due to differences in mean body weight at slaughter age as well as housing conditions. Therefore, further studies on the risk factors in relation to management and housing conditions are required.

In most European countries broilers are currently caught manually: broilers are caught by the leg, inverted and carried by a catcher with 3–4 birds in each hand. This method of catching broiler chickens is a welfare concern as it causes severe stress to the birds. A possible alternative to manual catching may be mechanical catching. The aim of this study was to compare the level of stress and injuries of broilers caught manually or with a harvesting machine (CIEMME Super Apollo L harvester) under commercial conditions. The results indicated that there was no significant difference in plasma corticosterone concentrations and duration of tonic immobility, which suggested that mechanically caught broilers were no more stressed than those caught manually. At the end of the catching process, mechanically caught broilers had even lower plasma corticosterone concentrations and shorter durations of tonic immobility, indicating that at this moment these broilers were less stressed than the manually caught birds. The incidence of wing haemorrhages was also reduced for broilers caught mechanically; however, there was no significant difference in the incidence of haemorrhages in the breast or legs between the two catching methods. As injuries are associated with pain and stress, this parameter is important not only for the welfare of the birds but also for product quality and the subsequent financial return. Therefore, it can be concluded that the use of the mechanical harvesting machine, CIEMME Super Apollo L, appears to be a good alternative to manual catching. Nevertheless, some aspects of mechanical catching require further improvement.

The effect of an environmental enrichment — straw bales — on the behaviour of growing broiler chicks was investigated by comparing the behaviour of broilers kept in matched pairs of houses on commercial farms with and without bales. The birds provided with bales perched on them and clustered around them. The most striking result, however, was that, even away from the bales, birds in the enriched houses were more active (showing more walking and running and less sitting) than birds in unenriched houses. The study provides support for the ‘Freedom Food’ recommendation that activity in commercially kept indoor chickens can be increased by providing environmental enrichment in the form of straw bales.

Farm assurance schemes can set standards to assure compliance with specific requirements relating to animal welfare. As such, standards can be set to address genetic-related welfare problems in farm animals, such as those associated with fast growth rates in meat chickens (broilers) (Gallus gallus domesticus). Based on discussions with broiler breeding companies, broiler producers and in line with published research, the RSPCA placed a maximum limit on the genetic growth rate potential of broilers that could be used within its own farm assurance scheme — Freedom Food. Despite the introduction of this requirement, the number of birds reared on the scheme increased from 25 million to 55 million per year over a three-year period, with all of these birds meeting the genetically slower growing requirement. In addition, the two largest global broiler breeding companies responded to this change in the market by each developing a genetically slower growing bird. This demonstrates that assurance schemes can have a pivotal role in tackling genetic welfare problems in farm animals, such as those associated with fast growth in broilers.

Despite recent technological advances, stunning efficiency of broilers in commercial plants is still questionable and a major public concern. The aim of this survey was to assess the electric water-bath parameters used in poultry processing plants, establish practical ways for the assessment of stunning efficiency in these conditions, link their incidence to the applied current and propose methodology for the online evaluation of the effectiveness of electrical water-bath stunning. A total of 5,378 broilers were assessed randomly for signs of post-stun recovery at 4, 8, 13 and 25 s post-water-bath exit (WBE) through corneal reflex, rhythmic breathing, head shake and escape behaviour on three processing lines. The electric water-bath parameters used did not meet the recommended current and frequencies for effective stunning. No rhythmic breathing was detected with any of the birds at 4 s post water-bath exit, while this reflex returned by 8 s in some birds. Broilers that had their necks cut had a significantly lower incidence of breathing compared to those that missed the neck cutter. The electric water-bath stunners that were tested did not abolish the corneal reflex where 38.4% of birds tested positive, at 4 s post WBE. Pulsed DC-stunned birds that missed the knife had a significantly higher incidence of positive corneal reflexes than those that had their necks cut. Head shake was present on 26.7% of the birds when assessed at 25-30 s post WBE. The trends in incidence of behavioural reflexes with time post WBE may be used for the assessment of stunning efficiency, particularly on birds that miss the knife, but none of the assessed indicators could unequivocally demonstrate unconsciousness.

Freedom from thirst has been long considered of paramount importance for animal welfare, however a feasible and sensitive animal-based indicator to assess thirst, on-farm or at-slaughter, is not available. In this study, voluntary water consumption over time was investigated and validated as a non-invasive behavioural parameter for assessing thirst in broiler chickens. Thirty-two groups of four broilers were used in this study and the effect of three factors on water consumption from a test drinker was investigated: duration of water deprivation (0, 6, 12, or 24 h); familiarity with the test drinker, and age (35 or 37 days). Water consumption was measured after 30, 60, 90 and 120 min following the deprivation period. Water consumption increased with the length of the deprivation period and was greater in birds that had been habituated to the test drinker. The effect of familiarity was smaller for 24-h deprived groups compared to 6- and 12-h deprived groups. When birds were habituated to the drinker, they started to drink sooner than when the drinker was new. These findings illustrate the potential of simple, animal-based measures, such as water consumption over time to assess thirst in chickens and this behavioural test may form the basis of an on-farm test that could be included in integrated animal welfare assessment schemes.

This study was performed to identify whether non-focal transcranial magnetic stimulation (TMS) with an adapted coil for broilers has the potential for use as a non-invasive stunning method for broilers. Application of the TMS probe resulted in dominance of theta and delta waves and appearance of spikes in the electroencephalogram (EEG) after stimulation. Correlation dimension (CD) analyses of the EEG signals recorded prior to and following the application of TMS suggested that the birds might be unconscious for approximately 15 to 20 s assuming that a reduction in CD to 60% of the baseline value indicates unconsciousness. Other observations included loss of behavioural arousal or muscle tone (muscle flaccidity), and irregular heart rate after TMS. It can be suggested that TMS has the potential to be developed as a stunning method in the future. The technique, evaluated using small number of broilers in this study, requires further improvement and the use of a power supply optimised in future research. Transcranial magnetic stimulation of the brain has potential for application as a non-invasive stunning method for broilers, which could be acceptable to some religious groups opposed to the use of established or conventional stunning methods.

The most significant welfare problems associated with the current design of the shackle lines and water-bath stunners are the pain caused by compression of the birds’ legs in the shackles, the stress caused by being inverted and suspended by the legs, poor or inadequate stunning caused by the commercial need to minimise carcase damage, and poor water-bath entry. Research is described in which some practical solutions to these problems were investigated. The aim is to identify solutions that individually, or jointly, could be retro-fitted to existing plants, or incorporated into the design of new, small processing plants to improve poultry welfare. The development and commercial availability of such systems would enable small, local and niche market poultry processing lines to continue operating following the implementation of EC Council Regulation No 1099/2009.

Broiler chickens are among the main livestock sectors worldwide. With individual treatments being inapplicable, contrary to many other animal species, the need for antimicrobial use (AMU) is relatively high. AMU in animals is known to drive the emergence and spread of antimicrobial resistance (AMR). High farm biosecurity is a cornerstone for animal health and welfare, as well as food safety, as it protects animals from the introduction and spread of pathogens and therefore the need for AMU. The goal of this study was to identify the main biosecurity practices associated with AMU in broiler farms and to develop a statistical model that produces customised recommendations as to which biosecurity measures could be implemented on a farm to reduce its AMU, including a cost-effectiveness analysis of the recommended measures. AMU and biosecurity data were obtained cross-sectionally in 2014 from 181 broiler farms across nine European countries (Belgium, Bulgaria, Denmark, France, Germany, Italy, the Netherlands, Poland and Spain). Using mixed-effects random forest analysis (Mix-RF), recursive feature elimination was implemented to determine the biosecurity measures that best predicted AMU at the farm level. Subsequently, an algorithm was developed to generate AMU reduction scenarios based on the implementation of these measures. In the final Mix-RF model, 21 factors were present: 10 about internal biosecurity, 8 about external biosecurity and 3 about farm size and productivity, with the latter showing the largest (Gini) importance. Other AMU predictors, in order of importance, were the number of depopulation steps, compliance with a vaccination protocol for non-officially controlled diseases, and requiring visitors to check in before entering the farm. K-means clustering on the proximity matrix of the final Mix-RF model revealed that several measures interacted with each other, indicating that high AMU levels can arise for various reasons depending on the situation. The algorithm utilised the AMU predictive power of biosecurity measures while accounting also for their interactions, representing a first step toward aiding the decision-making process of veterinarians and farmers who are in need of implementing on-farm biosecurity measures to reduce their AMU.

Effects of dietary supplemental stachyose on caecal skatole concentration, hepatic cytochrome P450 (CYP450, CYP) mRNA expressions and enzymatic activities in broilers were evaluated. Arbor Acre commercial mixed male and female chicks were assigned randomly into six treatments. The positive control (PC) diet was based on maize–soyabean meal, and the negative control (NC) diet was based on maize–non-soyabean meal. The NC diet was then supplemented with 4, 5, 6 and 7 g/kg stachyose to create experimental diets, named S-4, S-5, S-6 and S-7, respectively. Each diet was fed to six replicates of ten birds from days 1 to 49. On day 49, the caecal skatole concentrations in the PC, S-4, S-5, S-6 and S-7 groups were lower than those in the NC group by 42·28, 23·68, 46·09, 15·31 and 45·14 % (P < 0·01), respectively. The lowest pH value was observed in the S-5 group (P < 0·05). The stachyose-fed groups of broilers had higher caecal acetate and propionate levels compared with control groups, and propionate levels in the S-6 and S-7 groups were higher than those in the S-4 and S-5 groups (P < 0·001). The highest CYP3A4 expression was found in the S-7 group (P < 0·05), but this was not different from PC, S-4, S-5 and S-6 treatments. There was no significant difference in CYP450 (1A2, 2D6 and 3A4) enzymatic activities among the groups (P > 0·05). In conclusion, caecal skatole levels can be influenced by dietary stachyose levels, and 5 g/kg of stachyose in the diet was suggested.

Recently, Echinacea purpurea and its extracts have gained much interest due to their improvement on meat quality, but little information is available on the application of the purified Echinacea purpurea polysaccharide (4-O-methyl-glucuronoarabinoxylan, 4OMG). Thus, this trial aimed at assessing the effects of dietary supplementation of 4OMG on growth performance, thigh meat quality and small intestine development of broilers. A total of 240 1-day-old female broiler chicks were randomly distributed to four groups with three replicates of 20 within each group. Each group received either 0, 15, 20 or 25 g 4OMG/kg DM of diet. During the entire experiment, broilers had ad libitum access to water and feed, and the feed intake was recorded daily. All broilers were weighed before and end of the experiment. For each group, three pens with a total of 20 broilers were randomly selected to slaughter after 30 days. Increasing dietary supplementation of 4OMG linearly increased final live weight and daily body weight gain (P = 0.013) of broilers, Gain-to-Feed ratio (P < 0.001), muscle pH (P = 0.024) and redness (P = 0.001), but decreased drip loss (P = 0.033), shear force value (P = 0.004) and hardness (P = 0.022) of the thigh meat. Broilers fed diet with higher 4OMG had greater weight index, villus height and ratio of villus height to crypt depth in both duodenum and jejunum. These results indicated that increasing dietary supplementation of 4OMG was beneficial for growth performance, meat quality and development of the small intestine of broilers.

Decreasing heat increment through lowering crude protein (CP) level via supplemental amino acids (AA) have long been suggested as a nutritional practice to alleviate negative heat stress effects on broiler performance. However, there is a considerable body of inconclusive reports on optimisation of such practices, whereby bird performance remains unchanged. The exact mechanism underlying the impaired growth performance in birds fed with reduced-CP diets is not clear yet. Furthermore, adding the environmental temperature factor to the situation may complicate the solution. To date, there is no agreement on the extent of reducing CP level via AA supplementation so that growth performance remains unaffected. Evidence suggests that dietary CP could be reduced safely by 2.3% via essential AA supplementation during later ages, when birds are exposed to an average daily ambient temperature of ≤27.3°C. When Gly was added (a non-essential AA source), the margin of CP reduction could be increased to 5.1% without compromising the growth of broilers subjected to cyclic heat stress. Nonetheless, feeding broilers with a similar Gly-fortified, reduced protein diet failed to support optimal performance under hot and humid tropical climates in 1-21-d-old broilers and had a major impact on growth in broilers reared at 34°C. Regardless of supplemental AA composition or the level of CP reduction, the performance of broilers was negatively affected when birds were subjected to chronic heat stress conditions (≥30°C). These discrepancies can be attributed to a wide range of confounding factors, such as the extent of lowering CP level, types of AA used, age and environmental conditions. Accordingly, the addition of Gly may represent a good approach for reducing dietary CP levels for broilers raised under elevated ambient temperature. Reducing dietary CP is recommended when birds are exposed to moderate but not chronic heat stress conditions.

Recent data suggest that organic broilers often score worse on footpad lesions than conventional broilers but also that the current scoring of organic broiler feet may be misleading. In order to characterise footpad lesions in organic broilers, this study assessed and compared footpad lesions in a sample of 2987 conventional and 3578 organic broiler feet obtained from a large Danish abattoir during summer and winter. The feet were scored according to two scoring systems: the modified Danish surveillance scoring system and a histopathology-based new scoring system specifically developed to target the ability to differentiate between broiler feet with hyperkeratosis and ulcers. For both systems, all broiler feet with visible lesions were cross-sectionally incised. Significant differences between the two production systems were found for both scoring systems (χ2 = 710; P < 0.001 and χ2 = 247; P < 0.001 for the new and the surveillance systems, respectively), showing that a larger proportion of the organic feet compared to conventional feet – summer and winter – exhibited signs of hyperkeratosis. In addition, a smaller fraction of the organic feet than of the conventional feet were given the outermost scores, that is, normal or ulcerated; 13.4% v. 25.3% broiler feet were given score 0 for organic v. conventional production systems, respectively (χ2 = 152; P < 0.001), and 18.4% v. 23.8% feet were given score 4 for organic v. conventional production systems, respectively (χ2 = 308; P < 0.001). Thus, the results suggest that surveillance scoring systems such as the one used in Denmark are useful for the examination of footpad lesions in broilers from both types of production systems. However, the results have also raised attention to a typical characteristic of the feet of organic broilers, that is, profound hyperkeratosis, which may underlie potential misclassifications in surveillance scoring systems like the one used in Denmark. Among the possible solutions to this challenge to the correctness and fairness of the scoring system are improved procedures (such as mandatory incision), training of technicians and calibration of results (especially for the organic footpads).

The current experiment aimed at assessing the effects of dietary supplementation of guanidino acetic acid (GAA) on growth performance, thigh meat quality and development of small intestine in broilers. A total of 360 1-day-old female broiler chicks were distributed randomly to four groups of 90 birds each, and each group received GAA dosages of 0, 0.4, 0.8 and 1.2 g/kg of feed dry matter. During the whole experiment of 60 days, broilers had ad libitum access to water and feed and the feed intake was recorded daily. All broilers were weighed before and after the experiment, and 30 broilers of each group were selected randomly to slaughter at the end. Increasing dietary supplementation of GAA increased final live weight and daily body weight gain, gain-to-feed ratio, thigh muscle pH value and fibre diameter of broilers, but decreased daily feed intake, drip loss, cooking loss, shear force value, hardness, gumminess and chewiness of thigh meat. In addition, increasing supplementation of GAA quadratically increased duodenal, jejunal and ileal villus height and width and ratio of villus height to crypt depth, but decreased crypt depth. The results indicated that GAA as a feed additive may support better development of small intestine, thereby resulting in improvement of growth performance and meat quality of broilers.

A study was conducted to investigate the effect of method of whole wheat inclusion on performance and caecal microbiota profile of broiler chickens. Fluorescence in situ hybridisation analysis was used to characterise the microbiota by using genus-specific probes. Three treatments, namely, ground wheat (GW) or 200 g/kg whole wheat (WW) replacing GW before or after pelleting were evaluated. A total of 144, one-day-old male broilers (Ross 308) were allocated to 18 cages (eight broilers per cage) based on body weight and six cages were randomly assigned to each treatment. The diets were offered ad libitum from day 11 to 35 post-hatch. The WW fed birds, regardless of the method of inclusion, resulted in poorer weight gain (P < 0.05) and reduced feed intake (P < 0.001), but a similar feed per gain (P > 0.05) compared to those fed the GW diet. The WW diet, regardless to the method of inclusion, had no effect (P > 0.05) on the populations of Lactobacillus and Bacteroides spp. compared with the GW diet. The Bifidobacterium spp. population was higher (P < 0.05) in birds fed the GW diet compared with WW feeding, regardless of the method of inclusion. A reduction (P < 0.05) in the numbers of pathogenic Clostridium and Campylobacter spp. were observed in caecal samples from birds fed WW diets, regardless of method of inclusion, compared with those fed the GW diet, which was attributed to increased gizzard activity. Birds fed WW diets, regardless to the method of inclusion, showed a reduction in gizzard pH (P < 0.05), microbial gas production (P < 0.05), and an increase in gizzard weight (P < 0.05) relative to the GW treatment. The results indicated that the gizzard has an important function as a barrier organ, one that prevents pathogenic bacteria from entering the distal digestive tract.

Use of whole wheat, along with compounded feeds, for poultry feeding is a common practice in many parts of the world. However, studies investigating the use of other grains are limited. In the present study, the influence of including whole maize, with differing hardness, in broiler diets on the performance, nutrient utilisation and digestive tract development was examined. The experimental design was a 3 × 2 factorial arrangement of treatments, evaluating maize hardness (hard, semi-hard or soft) with diets based on ground maize or 115 g/kg whole maize replacing ground maize. The three maize cultivars were ground in a hammer mill to pass through a 4 mm sieve and six diets were developed based on one of the three cultivars. Following mixing, all diets were cold pelleted through a 3 mm die. Each of the six diets was fed to six replicate cages (eight birds per cage) from day 1 to 21 post-hatch. Maize hardness and whole maize inclusion had no effect (P>0.05) on weight gain. Maize hardness influenced (P<0.05) feed intake and feed per gain, while these two parameters were unaffected (P>0.05) by the inclusion of whole maize. The apparent metabolisable energy (AME) was unaffected (P>0.05) by maize hardness and whole maize inclusion. Maize hardness increased the ileal digestibility of nitrogen (P<0.05) and starch (P=0.06). The relative weight of the gizzard was greater (P<0.05) in birds fed hard and semi-hard maize compared to soft maize, and was greater (P<0.05) when whole maize was included. These results indicated that 115 g/kg of ground maize can be replaced by whole maize in broiler starter diets with no adverse effects on growth performance and thus can reduce the cost of feed manufacture.