Access to Barrier Perches Improves Behavior Repertoire in Broilers

Abstract

Restriction of behavioral opportunities and uneven use of space are considerable welfare concerns in modern broiler production, particularly when birds are kept at high densities. We hypothesized that increased environmental complexity by provision of barrier perches would help address these issues by encouraging perching and enhancing use of the pen space across a range of stocking densities. 2,088 day-old broiler chicks were randomly assigned to one of the following barrier and density treatment combinations over four replications: simple barrier, complex barrier, or control (no barrier) and low (8 birds/m2), moderate (13 birds/m2), or high (18 birds/m2) density. Data were collected on focal birds via instantaneous scan sampling from 2 to 6 weeks of age. Mean estimates per pen for percent of observations seen performing each behavior, as well as percent of observations in the pen periphery vs. center, were quantified and submitted to an analysis of variance with week as the repeated measure. Barrier perches, density and age affected the behavioral time budget of broilers. Both simple and complex barrier perches effectively stimulated high perching rates. Aggression and disturbances were lower in both barrier treatments compared to controls (P<0.05). Increasing density to 18 birds/m2 compared to the lower densities suppressed activity levels, with lower foraging (P<0.005), decreased perching (P<0.0001) and increased sitting (P = 0.001) earlier in the rearing period. Disturbances also increased at higher densities (P<0.05). Use of the central pen area was higher in simple barrier pens compared to controls (P<0.001), while increasing density above 8 birds/m2 suppressed use of the central space (P<0.05). This work confirms some negative effects of increasing density and suggests that barrier perches have the potential to improve broiler welfare by encouraging activity (notably by providing accessible opportunities to perch), decreasing aggression and disturbances, and promoting more even distribution of birds throughout the pen space.

Effects of perch availability on performance, carcass characteristics, and footpad lesions in broilers

“…A similar pattern for perching behavior has been reported in other studies (Pettit-Riley and Estevez, 2001;LeVan et al, 2000). Ventura et al (2012) also reported a general trend for different density treatments (8, 13, and 18 birds m −2 ) that perching increased up to the fourth week and then declined. Hongchao et al (2013) reported an average of 7.4 % perching, with the maximum perching ratio occurring at the fifth week comparable to the current study.…”

“…Similar results were reported by Pettit-Riley and Estevez (2001), Estevez et al (2002), and Ventura et al (2012). Although Zhao et al (2013) reported beneficial effects of cooled perching on feed conversion ratio and body weight gain, these effects were related to a thermoregulatory advantage of the cooled perches.…”

“…Theoretically, perches have the potential to reduce stocking density at floor level (Hughes and Elson, 1977), decrease health problems related with stocking density, such as reduced leg problems through exercise (Haye and Simons, 1978); improve heat stress conditions by allowing air flow beneath the perches to help thermoregulation of birds (LeVan et al, 2000); decrease aggression; and promote more even distribution of birds within the pen space (Ventura et al, 2012).…”

“…A limited improvement of footpad health by use of simple barrier perches has been reported (Ventura et al, 2010). Ventura et al (2012) reported that simple barrier perches could be a cheap and simple strategy to improve broiler health and welfare by creating a more complex environment to increase activity level and providing more space for resting, as well as decreasing aggression. Use of perches has been reported among environmental improvements that have been shown to increase activity and welfare of broilers in sheds (SCAHAW, 2000).…”

Flock size during rearing affects pullet behavioural synchrony and spatial clustering

“…We found no significant effect of group size on the overall number of disturbances of resting or preening birds, indicating that larger group sizes per se, in the absence of a corresponding increase in bird density (Febrer et al, 2006;Ventura et al, 2012), did not cause birds to interrupt the behaviour of others more often. Although birds were more clustered in space in smaller groups, their behaviour was also more synchronised, reducing the chance that resting and preening birds would be disturbed by more active birds.…”