What would cause this swelling?

[Going Quackers]

This is an example of a chick i had hatch.. now this chick did make it and we're now day 3 and the chicks swelling has subsided and it's seems all normal..

These were hatched by my broody but NOT My eggs, as she has no access to a rooster...

 

[linuxman]

Some chicks are like this. My personal thought, (nothing real sciency, get another opinion) is that is is just a large amount of yolk that the chick absorbs just before it hatches.

 

[Going Quackers]

Thanks.. usually if it was just the belly i would think that but the head swelling i thought very odd.

 

[Farmer Viola]

it could be caused by a very large egg. excessively large eggs will have a lot more egg white/albumen inside that the chick must absorb, resulting in a very bloated looking chick. Usually the yolk is the same size in a pullet or a old hen's egg, it's the albumen surrounding it that increases with eggshell size (in my experience). the swelling should start to go down after a day or three. the chick might also be sluggish during this time, and probably won't require food (or water?) while so bloated. I would still provide water to be sure though