The Influence of Size and Surface Condition of Grit Upon the Digestibility of Feed by the Domestic Fowl

Two experiments were carried out with growing cockerels to study the effect of size and surface condition of grit upon digestibility. The criterion employed to evaluate these effects was the apparent digestibility of the individual proximate constituents. Comparisons were made between six sizes of grit ranging in diameter from 0.6 mm. to 5.0 mm., and between four grits of different surface conditions.All grits utilized in this investigation significantly improved feed digestion. However, neither the size nor the surface condition of the grit influenced this response. Smaller sized grits, and grits displaying smoother-type surfaces were not retained within the gizzard to the extent of the rougher, larger sized grits; consequently a greater consumption of the former grits was experienced.