Diet preference tests for a wet versus dry feed, wheat structure and pellet size in broiler chickens

Diet preferences of broiler chickens were studied during 3 different choice-fed periods (P1, P2, P3). In P1 (1 to 7 days), chickens received a crumble starter diet with 250g/kg ground wheat (GW) in two separate feed troughs with dry and wet feed (1:1 feed to water). During P2 (8 to 21 days), chickens received diets in four separate feed troughs with whole wheat (WW) and GW in a 4 mm pelleted diet, fed dry and wet. In P3 (22 to 34 days), chickens received WW and GW dry pellets of 4 and 6 mm diameter in 4 separate feed troughs. Ingredient compositions of all diets from day 8 to 34 were similar (350g/kg wheat). Consumption from each feed trough was measured daily over a 6h-period. In P1, a strong preference for wet feed was found of 90.7% of total air-dry feed intake (P<0.001). In P2, preferences over the 4 diets were WW wet (62.6%), GW wet (33.7%), WW dry (2.6%) and GW dry (1.1%). Separate statistical analyses were done for the 6 slowest growing pens (SGP) (64g/d) and the 6 fastest growing pens (FGP) (70g/d). A positive correlation between average daily gain (ADG) and WW wet consumption was found for SGP (r=0.88, P=0.022) and a negative correlation for FGP (r=-0.83, P=0.042). Moreover, the ADG of FGP correlated positively with dry WW intake (r=0.81, P=0.050). In P3, preferences over the 4 diets were WW 6mm (33.4%), WW 4mm (33.2%), GW 4mm (24.3%) and GW 6mm (9.1%). Only FGP showed a preference for 4mm pellets (60.2% P= 0.005). The ADG of FGP were negatively correlated with WW intake in general (r=-0.83, P=0.039); no significant correlations were found for SGP. It is clear that chickens strongly prefer wet over dry diets and a high intake of a wet diet in combination with WW seems to benefit the slowest growing chickens. WW is preferred over GW, however a somewhat higher GW versus WW intake seems to benefit the faster growing chickens. The preference for 4 over 6 mm pellets seems to depend on growth rate and diet structure.