Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Feb 29;3:14.
doi: 10.3389/fvets.2016.00014. eCollection 2016.

Exposure to Increased Environmental Complexity During Rearing Reduces Fearfulness and Increases Use of Three-Dimensional Space in Laying Hens (Gallus Gallus Domesticus)

Affiliations
Free PMC article

Exposure to Increased Environmental Complexity During Rearing Reduces Fearfulness and Increases Use of Three-Dimensional Space in Laying Hens (Gallus Gallus Domesticus)

Margrethe Brantsæter et al. Front Vet Sci. .
Free PMC article

Abstract

The complexity of the rearing environment is important for behavioral development and fearfulness. The aim of this study was to test the hypothesis that laying hens reared in a complex aviary system with exposure to mild intermittent stressors would be less fearful, less sensitive to stress, and would use elevated areas of the pen more often as adults than hens reared in a barren cage environment. Laying hens (N = 160) were housed in the same rearing house; half of the birds (n = 80) in an aviary and the other half (n = 80) in cages. At 16 weeks of age, the birds were transported to the experimental facilities. Their behavior was recorded at 19 and 23 weeks of age and analyzed by analysis of variance on individual scores for a fearfulness-related principal component generated using principal component analysis. The results indicate that aviary-reared birds have lower levels of fearfulness compared with cage-reared birds both at 19 weeks and at 23 weeks of age. When comparing the response induced by initial exposure to a novel object at 19 and 23 weeks of age, more aviary-reared birds tended to fly up at 19 weeks compared to the cage-reared birds, indicating a tendency toward a more active behavioral response in the aviary-reared birds than in cage-reared birds. There was no difference between treatments in the flight response at 23 weeks. The groups did not differ in defecation frequency or the concentration of fecal corticosterone metabolites at either age. At 19 weeks, observation of the spatial distribution in the home pens indicated that more aviary-reared birds spent time on the low perch, the elevated platform, and the upper perch, compared to the cage-reared birds. However, at 23 weeks of age, these differences were no longer detected. The results of this study support the hypothesis that increased environmental complexity during rearing reduces fearfulness of adult laying hens.

Keywords: behavior; chicken; fear; fearfulness; laying hen; rearing; stress.

Figures

Figure 1
Figure 1
Figure illustrating the test arena where the human approach test and the novel object test was performed. The human or novel object (NO) was positioned just outside the transparent wall. The birds were placed in the arena through the start box (S). The EthoVision XT camera was mounted in the ceiling above zone 3 and pointed down. There was an additional camera (cam) next to the human/novel object. Numbers 1–5 represent zones of increasing distance from the test stimuli.
Figure 2
Figure 2
Mean ± SD scores for Component 1 for aviary-reared and cage-reared birds at 19 and 23 weeks of age. Principal component analysis was conducted to generate individual scores for a component measuring “fearfulness” (scores for Component 1). To avoid negative values, three was added to all component scores in the figure. Significant differences are marked *.
Figure 3
Figure 3
Figures showing the flight response for aviary-reared and cage-reared birds at 19 and 23 weeks of age. Black columns indicate aviary-reared birds. White columns indicate cage-reared birds. The x-axis indicates the zone. Zone 1 was closest to novel object and zone 5 was the start zone farthest away from the novel object. The y-axis indicates the number of birds that did not fly at 19 weeks of age (A), the number of birds that flew at 19 weeks of age (B), the number of birds that did not fly at 23 weeks of age (C) and the number of birds that flew at 23 weeks of age (D).

Similar articles

See all similar articles

Cited by 4 articles

References

    1. Boissy A. Fear and fearfulness in animals. Q Rev Biol (1995) 70(2):165–91.10.1086/418981 - DOI - PubMed
    1. Mills AD, Faure JM. Panic and hysteria in domestic-fowl – a review. In: Zayan R, Dantzer R, editors. , editors. Social Stress in Domestic Animals. Dordrecht: Kluwer Academic Publication; (1990). p. 248–272.
    1. Anderson KE, Adams AW. Effects of cage versus floor rearing environments and cage floor mesh size on bone strength, fearfulness, and production of single comb white leghorn hens. Poult Sci (1994) 73(8):1233–40.10.3382/ps.0731233 - DOI - PubMed
    1. de Haas EN, Bolhuis JE, Kemp B, Groothuis T, Rodenburg TB. Parents and early life environment affect behavioral development of laying hen chickens. PLoS One (2014) 9(3):e90577.10.1371/journal.pone.0090577 - DOI - PMC - PubMed
    1. Gilani AM, Knowles TG, Nicol CJ. The effect of rearing environment on feather pecking in young and adult laying hens. Appl Anim Behav Sci (2013) 148(1–2):54–63.10.1016/j.applanim.2013.07.014 - DOI

LinkOut - more resources

Feedback