The Effects of Origin on the Formation of Stress Parameters and Selected Behaviour of Hens

The aim of this study was to evaluate the effect of the origin of hens of locally adapted breeds on the levels of selected stress indicators and neurotransmitter serotonin in blood, and also on the selected behaviour and plumage condition. A total of 168 one-day-old chicks of the hens Leghorn H-22, Sussex S-66 and Rhode Island Red R-11 were allocated to three experimental groups, respectively: 1, 2 and 3. The birds were reared on litter until 64 weeks of age. Bird mortality was monitored during the experiment, the duration of tonic immobility (TI) was measured and blood was collected and the following were determined: heterophil-to-lymphocyte ratio (H:L), levels of corticosterone, adrenaline, noradrenaline and serotonin. Behavioural observations were also made and the plumage condition of the hens was also assessed. The hen strains studied showed different levels of fear and stress during rearing, as reflected in the behavioural test carried out and the blood levels of basal corticosterone, noradrenaline and the H:L ratio. It was also shown that changes in the birds' fear and stress response strategies can occur with age. H-22 hens showed greater fear and stress at both young age and adulthood, and were characterised by poorer plumage and higher mortality during rearing. The results, therefore, suggest that strain H-22 has a greater propensity to develop stereotypes such as feather pecking compared to strains S-66 and R-11.