A gentling program decreases fear-related behaviour towards humans but not towards novel objects in broiler chickens (2025)

Stocker, T., Nawroth, C., Puppe, B. et al.

Abstract

The human-animal-relationship is a crucial aspect of good animal welfare. Improvements in this regard might be particularly relevant for chickens, as their relationship with humans in commercial husbandry conditions is often limited to brief animal inspections (visual contact) on a daily basis. Regular human contact can potentially reduce fear responses towards humans in chickens, but to achieve this, a long period of several weeks of habituation is usually required. In this study, we investigated whether a short period of ‘gentling’ (i.e. standardised human-animal interactions that the chicks are likely to perceive as positive) within the first 3 days of life would be sufficient to reduce fear responses towards humans in broiler chickens. Six groups of ca. 220 (214 – 254) day-old broiler chicks each were exposed to a gentling program by a human after arrival. The same number of control groups received no human contact apart from routine husbandry procedures. We performed three behavioural tests on the chickens to assess their fear of humans. A stationary person test (SPT) measured the voluntary approach to a standing human, an avoidance distance test (ADT) measured the avoidance behaviour towards an approaching human while a touch test (TT) measured the approach behaviour towards a squatting person followed by the measurement of the avoidance behaviour from the approaching hand. Additionally, a novel object test (NOT) was performed to assess whether a potential fear reduction would be limited to humans. The tests were conducted at three different ages of the chickens (day 7, 21 and 36). In all human-related tests, chickens of the gentled groups showed less avoidance and more approach behaviour towards the human than chickens of the control groups (SPT: p = 0.004, ADT: p = 0.001, TT: p = 0.035). The results of the NOT showed statistically no significant behavioural differences between the gentling and control groups (p = 0.205), confirming that the chicks’ fear responses are not generalised but specific to human-related tests. The present study suggests that gentle handling of chickens during the first 3 days of life can improve the human-animal-relationship for at least 36 days.