Effect of Transport Cage Height on Broiler Live Shrink and Defecation Patterns

Abstract

A series of eight trials was conducted to determine the effect of transport cage height on broiler defecation patterns during holding. Prior to treatment, broilers were held in pens with free access to feed and water. In each trial, birds were randomly placed into nine experimental cages, allowing a bird density of 447 cm2/bird. Cages were constructed of wire with perforated wooden tops set at internal heights of 15.2 cm (short), 22.9 cm (normal), or 68.6 cm (tall). The “normal” height was determined as an average for commercial broiler transport cages. Cages with broilers inside were weighed, placed over preweighed manure catch pans, and held for 8 h at 26°C; the cages and the pans were reweighed to determine live shrink and excreta weight. In the first two trials, birds held in the short cages had a significantly greater live shrink than the broilers in the normal or tall cages. However, observations that the cage designs might have adversely affected ventilation led to a redesigning of the tops using wire fabric to improve ventilation. In the following six trials, cage height had no significant effect on live shrink (4.2%) or excreta (1.8%). These results indicate that transport cage height, relative to bird posture during transport, had no significant effects on live shrink or defecation patterns of broilers.