Patch discrimination as a function of handling time.
We tested male broiler chickens in 3 experimental group sizes (GS) to examine the mediating effects of GS and feed handling time on patch choice. We tested the experimental GS in a 3-patch discrimination trial with patches that contained identical amounts of feed but differed in the proportion of inedible filler material (wood shavings) added. The patch requiring the least handling time offered the highest profitability and was composed of 25% filler and 75% feed (by volume), whereas the mid and low profitability patches contained 50 and 75% filler, respectively. Food consumption, foraging duration, patch residence time, number of foraging bouts, and number of discrete patch visitors were significantly greater at the more profitable patches, requiring less handling time. We found a greater number of birds exploiting all 3 patches at larger GS, although we did not detect a parallel increase in aggression. On the contrary, aggression increased only as handling time decreased. These results suggest that at large GS resource monopolization did not occur; birds were most likely involved in scramble competition, particularly at the more profitable patches. Our findings show that broilers are able to discern the handling time required to obtain nutritious feed and adjust their foraging behavior according to the number of competitors.
Leone
E H
EH
Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA.
Estévez
I
I
D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D002645:Chickens / Q000502:physiology*; D005247:Feeding Behavior; D008297:Male