A meta-analysis of hematological parameters allowed comparison of domesticated chickens (commercial or indigenous) with the ancestral red jungle fowl, with wild birds in the order Galliformes and with wild birds. Major differences were observed with hematocrit (hct)/packed cell volume (pcv). The hct/pcv was very similar between the ancestral species from which chickens were domesticated, the red jungle fowl (Gallus gallus) and wild birds in the order Galliformes. However, the hct/pcv was lower in indigenous non-selected chickens than either the red jungle fowl or wild birds in the order Galliformes. The hct/pcv was further reduced in commercial chickens. Moreover, the hct/pcv was lower in wild birds in the order Galliformes than other wild birds.The present analyses support a consistent shift in declining hct/pcv in the development of modern poultry. There was no evidence that there are any shifts in hct/pcv or the heterophil:lymphocyte ratio in response to stress in chickens.
Scanes CG, Christensen KD. Comparison of Meta-analysis of the Hematological Parameters of Commercial and Indigenous Poultry to Wild Birds: Implications to Domestication and Development of Commercial Breeds/lines. J Vet Sci Anim Health. 2014;1(1):1-12.