Dauntless dual-purpose hens: comparing fear related responses between two chicken strains

Excessive fear in captive animals can lead to chronic stress, and thus impair animal welfare. In laying hens, fearfulness has also been associated with the occurrence of feather pecking. The aim was to comparatively assess fear related responses of conventional layer hybrids (Lohmann Brown plus, LB+) and dual-purpose hens (Lohmann Dual, LD), which seem to be less prone to injurious pecking. Therefore, three consecutive batches of LB+ and LD hens were kept in four compartments of an aviary system (about 900 hens/compartment) under the same management conditions. The hens were studied from 21 to 69 weeks of age (batch 1 and 2), and from 21 to 56 weeks (batch 3). In order to assess fearfulness, a novel object (NO) and an avoidance distance (AD) test following standard protocols were carried out in both hybrids at a group level at 7 (batch 1 and 2) and 5 (batch 3) different ages during the laying period. A higher number of LD hens was observed near the NO at 30 weeks of age, and between 47 and 69 weeks (F1,62= 4.30-9.11 (depending on week), P<0.05). In addition, they also approached the NO sooner compared to the LB+ hens (F1,62=6.41-15.50 (depending on week), P<0.05). Similarly, the LD hens retreated at smaller distances from a human in the AD test from 40 to 69 weeks of age (F1,62= 4.85-17.30 (depending on week), P<0.05). During the first observation times (21/30/40 weeks of age), differences in fear levels between the two hybrids were not significant but detectable at the descriptive level. The present results indicate that dual-purpose hens act less fearful in the performed behavioural tests compared to conventional layer hybrids. Therefore, dual-purpose hens might experience less stress during daily management routines, which would affect animal welfare positively.