Look for lesions like on your hen's wattles, but with chicks it would be around the eyes or on the beak. If you do notice lesions on the chicks, then I would
watch them closely to see if they are eating/drinking well and not having any trouble there, maybe even look inside their beaks a few times a week to make sure there's no evidence of wet Fowl Pox.
I'm not trying to scare you, it may not turn out to be anything and those lesions are exclusive to the broody and not affect the chicks at all. But...Fowl Pox is harder on chicks so just keep watch on them is all I'm saying.
Be sure to post some photos of them!