Research Note: Effect of stocking density on crop fill progression in broilers grown to 14 d

Abstract

Crop fill rates are measured as an indirect means of assessing management during the brooding phase. Primary breeder guidelines indicate that 95% of the chicks assessed should present a crop that is full, soft, and rounded after 24 h, which indicates chicks have successfully located feed and water. Crop fill progression has received little attention in the scientific literature and is primarily discussed in trade literature, and thus, the dynamic nature of crop fill progression has not been previously characterized. This study examined the role of 2 market weight stocking density treatments (29.3 kg/m² and 43.9 kg/m²) on performance and crop fill of broilers grown to 14 d. Crop fill progression was observed at 2, 4, 8, 12, 24, and 48 h after placement and tracked BW of birds that presented empty crops at 24 h; chicks with empty crops were identified to track postplacement BW. Stocking density had no significant effect on bird performance or crop fill. At 24 h, 86% of birds in this study had full, soft, and rounded crops, while only 3% of birds had crops that were devoid of food or water at 24 h. BW for birds with empty crops was significantly lower at 7 d (P = 0.006) but not at 14 d (P = 0.535). The data herein indicate that crop fill rates of 95% or higher at 24 h may be difficult to achieve in typical commercial broiler settings. In addition, assessing crop fill may be a useful tool to diagnose conspicuous management problems during brooding, but it does not appear to be a direct predictor of early performance.

Keywords: broiler; crop fill; stocking density.