When you are raising baby chicks from their early stages of development, your chicks could develop something called "pasty butt."
Chickens have one hole that is used for laying eggs, pooping, urinating and mating. This hole is called the cloacal vent. A chick's mother hen keeps her chicks' cloacal vents clear, but if you are raising the chicks yourself, the vent can become clogged and you end up "pasty butt." I have read that this can happen during shipping – some say from temperature changes, some say from stress. A chick can actually die from pasty butt because it cannot poop until the pasty butt is cleared. The result: you need to clean your chicks' bottoms. Use a warm wash cloth and move it slowly on the chicks' bottoms. You can use a Q-tip and olive oil or mineral oil to rub around the vent and surrounding area.
Some people actually run the pasty butts under warm water to help dissolve the poo. Make sure your room is well heated. Dry the chicks off before putting them with the other chicks so their bottoms do not draw attention. You may end up plucking some of the pasty goop, irritating the skin, which then may cause other chicks to peck at it.
Check your chicks' bottoms daily for the first few days to look for buildup.
When your chicks first arrive, give them sugar water the first day to help increase their energy levels; feed them chick starter food and scrambled egg. Yes, egg. I know it sounds cannibalistic.
In the meantime, watch those chicken butts! This YouTube video shows what it looks like and demonstrates the cleaning technique: