Tonight I noticed a 3-week-old chick has a prolapsed vent. The vent is pooched out about a quarter inch and is bright red. The chick's backside is splashed with whitish poo. While I washed off its behind there was a trickle of more whitish stuff coming out. I noticed there was something wrong when I picked up the chick tonight & noticed it felt lighter than it should. It's crop wasn't full like it should be at that time of day. Otherwise, the chick is active & fairly perky. I put some sugar on the protruding vent. We'll see how much improvement there is by morning. It lives with only one other chick, and that chick isn't bothering the prolapsed one. What causes this? Can it be effectively cured at this age, or will it grow up into a hen that has frequent blow-outs? Would it be kinder to cull?