Baxter, M., O’Connell, N. E. 2019. Does grouping environmental enrichments together affect the way they are used by commercially housed broiler chickens? Applied Animal Behaviour Science 210, 52-59.

Identifying the most attractive ways of presenting environmental enrichments in commercial broiler housing may encourage use and optimise their effectiveness. This study investigated the effect of grouping straw bales (SB), oat hulls (OH; as a dustbathing substrate) and pecking chain (Pe) together, compared to providing individual enrichments, on level of enrichment use and the behaviour of proximate broilers. Approximately 56 000 Ross 308 broiler chickens were placed in two matched commercial houses on one farm (max. 30 kg/m2). On day 4, SB, OH (in steel rings 1.1 diameter, 7.62 cm deep), and black/yellow plastic Pe were introduced. These enrichments were grouped into seven enrichment combinations per house: 1) SB only, 2) OH only, 3) Pe only, 4) SB + OH, 5) SB + Pe, 6) OH + Pe, and 7) SB + OH + Pe. The farm was visited twice weekly over one production cycle in weeks 2, 3, 4 and 5. Behavioural data were collected using scan and focal sampling from video footage. Each enrichment type was compared with its three alternative combinations. In general, level of use of SB and OH was similar to previous research, but use of Pe was higher than anticipated. Enrichment combination did not have a significant effect on the number of broilers around the straw bales or in the oat hull rings, or on the types of behaviours observed. Focal observations of direct enrichment use revealed that significantly more vertical wingshakes were performed when the oat hulls were placed singly (OH) rather than in the SB + OH + Pe combination (P = 0.026). There was a significant interaction between enrichment combination and week for the number of pecks directed at the straw bales (P = 0.013), and no effect of enrichment combination on the number of pecks directed at the pecking chain (P > 0.05). Specific effects of placing SB close to OH (as a possible form of vertical cover) on levels of dustbathing and disturbance was examined, but no significant effects were found. In conclusion, we found no obvious benefits to grouping these enrichments together rather than providing them singly, and some practical benefits to placing enrichments individually (such as more even distribution of fresh straw throughout the house). Straw bales did not appear to offer significant protective cover around dustbathing areas, with no increase in comfort behaviours or reduction in disturbances observed. Broilers were substantially more interested in pecking chain than has been previously reported, highlighting the need for more commercial scale research.