Use of horizontal and angled perches by broiler chickens

Roosting increases the survival of wild relatives of domestic birds. Thus, we expected chickens to choose to roost on perches. We predicted that birds would use angled perches more than horizontal ones because an angled roost would be more similar to tree branches and thus more attractive to the bir ds, and also easier for the birds to access. We assigned 768 male broilers to 16 pens in a 4 treatment X 4 replication randomized complete block desig n. Each of the four pens within each block contained one of the following t reatments: 0 degrees treatment (three 0 degrees perches); 20 degrees treatm ent (three 20 degrees perches); mixed angle treatment tone 0 degrees, 10 de grees and 20 degrees perch); and a control (no perches). Angled perches wer e designed to slope upward from the floor to facilitate access to the perch es by broilers at all ages. A combination of differently angled perches wit hin the same pen (mixed angled treatment) provided more roosting choices at all ages, as well as allowed the birds to use different angled perches as their size and strength changed with age. The perch designs differed signif icantly only in height at one end (slope). Perches were constructed of 1.9 cm inside diameter polyvinyl chloride (PVC) pipes, and were 91 cm in length with 5 equally spaced 28 cm long PVC crossbars. Perch use was recorded eve ry 15 min for three consecutive hours, 4 days each week from day 3 to 42 us ing instantaneous scan sampling. Mean perch use was low across all treatmen ts (2%), possibly due to heavy body weight and high ambient temperature in later weeks. However, distinct perching patterns were identified. Perch use was highest in the 0 degrees treatment and lowest in the 20 degrees treatm ent. Within the mixed angle treatment, 0 degrees perch use was highest, fol lowed by 10 degrees and 20 degrees perch use, respectively. Perching genera lly increased with age bur peaked at week 5. A decline in perching occurred at week 6, a period during which the birds had the heaviest body weights a nd ambient temperatures remained high. We determined that perching increase d with age of bird (through week 5), decreased with hotter temperatures, wa s greater for perches with lower angles (0 degrees and 10 degrees), and fol lowed a daily crepuscular pattern. (C) 2000 Elsevier Science B.V. All right s reserved.