Haematological parameters of laying hens under different group size

Abstract

The relevance of this study lies in its potential implications for poultry farming practices and animal welfare. Understanding the impact of group size on the blood parameters of hens can provide valuable insights for optimising their health and well‐being in farming environments. The aim of the study was an analysis of haematological parameters of laying hens under the influence group size with the same stoking density in analogous cages by design. Hens were kept for 34 weeks in cages of multilevel batteries at different group sizes: I group—93 birds, II group—52 birds, III group—17 birds and IV group—9 birds. The study analysed blood samples from laying hens at 18 and 52 weeks of age. Results showed that reducing the group size from 93 to 52 birds led to a haematological status within the physiological norm, characterized by increased heterophils and decreased monocyte levels. Whereas, the decrease in group size to 17 birds was accompanied by a decrease in the hens' blood content of thrombocytes, an increase of heterophile, a decrease of monocytes and lymphocytes within the physiological norm, as well as an increase in the heterophiles to lymphocytes ratio.