Passage rate of feed in very young chicks

White Leghorn chicks were reared on diets in which soybean oil at 4% or corn oil at 5 or 10% was substituted isocalorically for carbohydrate calories. The transit time ( TRT ) of diets was determined in these chicks with ferric oxide as a marker. The average TRT for three experiments was 167 min. Overall, there was no significant effect (P greater than .05) for the addition of the vegetable oils to alter TRT . A significant interaction was detected for TRT to be shorter as chicks aged from 7 to 21 days of age when provided with 4 to 5% vegetable oil but not when provided with 10% corn oil. An extra metabolic effect was detected from the isocaloric substitution of lipid calories for carbohydrate calories but not necessarily only when TRT was longer. Thus, the chick was affected differently than the hen in which lipid produced longer TRT .