Effects of hatching system and enrichment on broiler chickens’ behaviour

After hatching in commercial hatcheries, chicks usually have no access to water and feed for 24 to 48 hours. This can
lead to decrease post-hatch development and impair animal welfare. One alternative to avoid this problem is on-farm
hatching. Enrichments of the housing environment can be offered to further promote animal welfare. To investigate
the influence of hatching system and additional enrichment on behaviour, 320 mixed-sex broilers were kept in a
2×2 design (hatchery-hatch vs on-farm hatching × barren environment vs enriched). Environmental enrichment was
provided by elevated structures (plastic grids). Individual chickens were tested twice, in an arousal test (test arena in
the pen, duration: three minutes) on day 5 and in an open field test (test arena outside the pen, duration: five minutes)
on day 25 of life. Latency to first move, number of field changes, and amount of defecation were recorded. Additionally,
enrichment usage in the pens was analysed throughout the cycle. Statistical analyses were done with linear mixedeffect
models using nlme package in R and we tested for correlations of test parameters between day 5 and 25. The
usage of elevated structures was higher in on-farm hatched than in hatchery-hatched chickens (P=0.0312). On day 5,
chickens hatched on-farm showed a longer latency to first move compared to the hatchery-hatched birds (P=0.0052).
At day 5, chickens from barren environment tended to show more field changes than animals kept with enrichment
(P=0.08) in the arousal test. On day 25, chickens from the enriched environment showed more field changes (P=0.016).
Only a weak correlation was found between day 5 and day 25 in the latency to first move (rP=0.134, P=0.017). Both
treatments affected different behavioural traits, parameters in various extent: on-farm hatched chickens showed more
fear in early life. Furthermore, chickens kept in a barren environment were more active.