if you have a dispenser that faces either east or west and it fires an egg into a 1 block area the baby chicken gets stuck in the dispenser and in some cases can be pushed through and/or suffocate and die. This does not happen in vanilla.

to replicate:
build what is shown in the screenshot and make sure the dispenser is facing either east or south. fill it with eggs and connect it to a redstone clock.
although the chickens may not get stuck at first, if something pushes them (like a player or a bunch more chickens) they get stuck and get pushed into or through the dispenser almost every time