Crossbred Poultry. Hybrid Vigor. D. C. Warren, Agricultural Experimental Station, Manhattan, Kansas. Bulletin, 252.

Summary:

1. 1. Crosses between the Single Comb White Leghorn and Jersey Black Giant showed the resulting hybrids to be superior to the two pure breeds in all measurements of vigor.

2. 2. The results from the Single Comb White Leghorn-Single Comb Rhode Island Red cross showed the hybrids to be generally superior to the pure breeds, but in a few comparisons the hybrids only equalled the better of the two breeds involved.

3. 3. The crosses of Single Comb White Leghorns by Barred Plymouth Rocks and of Single Comb Rhode Island Reds by Barred Plymouth Rocks produced hybrids that in each case were superior to the pure breeds involved, for chick mortality and rate of growth, these being the only criteria of vigor considered.

4. 4. Crosses between independently bred strains of Single Comb White Leghorns produced offspring that were in some respects superior to the pure strain progeny, but the degree of stimulation did not appear to be so great as in the crosses of different breeds.

5. 5. Sex of chicks may be distinguished at hatching by means of sex-linked down colours in crossbred chicks.

6. 6. The new method utilising the growth of wing feathers at hatching is slightly less accurate for identifying the sexes, but has certain advantages over the down-colour method.

7. 7. The advantages of the wing feather growth method are that it makes available the White Leghorn breed, which is widely popular and well bred for production; it produces a white hybrid; and greatly extends the list of breeds available for crossing to distinguish sex at hatching.

8. 8. The superior vigour of some hybrids probably makes them more economical than most pure breeds for the poultryman whose major income is from market poultry and eggs.