Hi Ardizzone7,
Sometimes an egg will get cracked by the hen. Cracked eggs can rot and explode, getting yolk on the other eggs. I would not rinse off the eggs nor be concerned about it, but if she gets off the nest to eat again, you could check the bedding under the eggs to make sure it's not wet with yolk too. If it is, I would quickly change her nesting material with fresh material and place the eggs carefully back like she had it. Don't worry, she will make rearrange her eggs and get everything placed the way she wants it when she returns to her nest. Other than that, I would leave the hen to sit and check again in other day or so.
Normally a hen will lay a clutch of eggs and then sit. If you have other hens that can get to her nesting area, they could have continued to lay eggs in her nest after she began sitting and this could cause some of the eggs to hatch out later than others. I wouldn't get too concerned just yet.
If you purchased the eggs and then placed them all under your broody hen at the same time, then they should have a 21 day hatching cycle. There is always the chance of some late hatchers. I have had a hen hatch out one chick then four days later another 3 hatched. I just let the hen take care of everything. She seems to know much better than I what she is doing.
If you find any of the eggs pushed out of the nest and no longer under the hen, but off to the side getting cold to the touch, then I would toss those ones out. Hens seem to know when an egg has gone bad. Those stinky eggs make quite a mess when they explode.
Soon enough you should have some cute fluffy chicks peeking out from underneath her feathers.
I hope you have a successful hatch! Take care.
