The present study evaluated the effect of live insect larvae (Hermetia illucens, HI) supplementation as an environmental and nutritional enrichment on the behaviour of laying hens reared in a cage-free system. Along 5 weeks, 1800 laying hens of two genotypes (Novogen Brown and White) aged 36 to 40 weeks were randomly assigned to 8 pens of an experimental aviary. Live insect larvae were distributed (10% of the daily feed intake) in circular feeders once a day at 10 a.m. in four pens, whereas no enrichment was provided in the other 4 pens. Hen behaviour was assessed analyzing video recordings made 24 hours a day, one day a week. Data were submitted to ANOVA with live HI larvae supplementation, genotype, and hour of observation as main effects and the pen as a random effect by PROC GLIMMIX of SAS. The enrichment with HI larvae increased the number of hens observed on the floor (22.6 vs 24.2 hens; P<0.001), which were found pecking insects (1.64% of observed hens) and feeders (5.19%). The HI enrichment also decreased the rate of hens pecking the litter (54.8% to 52.8%; P<0.01), inactive (8.23% to 7.47%; P<0.001) and moving (18.8% to 16.8%; P<0.001) compared with the hens without enrichment. As for the effect of the genotype, more brown hens were found pecking the litter (56.2% vs. 51.5%; P<0.001), inactive (10.1% vs. 5.64%; P<0.001), and preening (14.0% vs. 9.93%; P<0.001) compared with white hens, whereas the latter ones showed more piling (3.60% vs. 0.62%; P<0.001) and locomotion (19.2% vs. 16.4%; P<0.01) behaviours. The human confidence test revealed that the man-hen distance was lower in hens that received live larvae compared with the control hens (23.3 cm vs. 55.6 cm; P<0.001), and lower in brown hens compared to white hens (12.6 cm vs. 66.5 cm; P<0.001). In conclusion, the use of live HI larvae as enrichment in diets for laying hens increased their behavioural repertoire and confidence towards humans, which could likely have improved their affective status. On the other, the use of enrichment did not impact on hen aggression and piling behaviours.
Behaviour of laying hens fed with live insect larvae (Hermetia illucens) as enrichment in a cage-free system
Pravato M.
;Bordignon F.;Ciarelli C.;Xiccato G.;Trocino A.
2025
Abstract
The present study evaluated the effect of live insect larvae (Hermetia illucens, HI) supplementation as an environmental and nutritional enrichment on the behaviour of laying hens reared in a cage-free system. Along 5 weeks, 1800 laying hens of two genotypes (Novogen Brown and White) aged 36 to 40 weeks were randomly assigned to 8 pens of an experimental aviary. Live insect larvae were distributed (10% of the daily feed intake) in circular feeders once a day at 10 a.m. in four pens, whereas no enrichment was provided in the other 4 pens. Hen behaviour was assessed analyzing video recordings made 24 hours a day, one day a week. Data were submitted to ANOVA with live HI larvae supplementation, genotype, and hour of observation as main effects and the pen as a random effect by PROC GLIMMIX of SAS. The enrichment with HI larvae increased the number of hens observed on the floor (22.6 vs 24.2 hens; P<0.001), which were found pecking insects (1.64% of observed hens) and feeders (5.19%). The HI enrichment also decreased the rate of hens pecking the litter (54.8% to 52.8%; P<0.01), inactive (8.23% to 7.47%; P<0.001) and moving (18.8% to 16.8%; P<0.001) compared with the hens without enrichment. As for the effect of the genotype, more brown hens were found pecking the litter (56.2% vs. 51.5%; P<0.001), inactive (10.1% vs. 5.64%; P<0.001), and preening (14.0% vs. 9.93%; P<0.001) compared with white hens, whereas the latter ones showed more piling (3.60% vs. 0.62%; P<0.001) and locomotion (19.2% vs. 16.4%; P<0.01) behaviours. The human confidence test revealed that the man-hen distance was lower in hens that received live larvae compared with the control hens (23.3 cm vs. 55.6 cm; P<0.001), and lower in brown hens compared to white hens (12.6 cm vs. 66.5 cm; P<0.001). In conclusion, the use of live HI larvae as enrichment in diets for laying hens increased their behavioural repertoire and confidence towards humans, which could likely have improved their affective status. On the other, the use of enrichment did not impact on hen aggression and piling behaviours.
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