In mammals it is well known the role of the elastic fibres in the lung development and its fundamental importance in the process of distending and recoil of the organ as a whole. The bird's lungs are compact and virtually non-expansible.

After morphological studies on elastic fibres distribution and quantification by image analysis we carried out a study on biochemical methods to quantify elastin in the avian lung, using domestic fowl (Gallus gallus) as an experimental model. We made use of two analytical methods for the elastin determination in these animal lungs from the 14th day of hatching until the 42nd day after hatchling.