They are northern fowl mites and, if you see them in the nest, she is infested. Dust her immediately with Diamotaceous Earth (DE) or 7 dust or give her a bath with doggy flea shampoo. Put the eggies in the bator if you have one... if you don't they will be fine on the counter for a few hours. ...in an egg carton so they don't roll off.. then they won't be fine
Clean out the coop, spray with either permethrin ($5 at
TSC) or sprinkle everything with DE... making sure to get in all the crevices, where they live. Put fresh nesting material mixed with DE back in the nest, replace your eggies and your broody. This should not interrupt her broodiness. IF it does, stick her back on there tonight and she should get back into the swing of things.
eta: It's warm enough outside to keep these eggs warm til tonight. I've had hens bail from the nest and I'll find the eggs 20+ hours later and they will still hatch... just don't have them in direct sun.
You cannot wait to do this because broodies are already not eating as much as they should and are getting weaker on the nest leaving them more suseptible to enemia. The chicks would get infested the moment they hatch and would, most likely die. If you do go the bath route, make sure you blow dry her and leave her under a heat lamp for a couple hours to make sure she's dry.
Good Luck and it's really no big deal. Broodies are easy lunch because they are restricted in that one area. This happens to everyone. Just be glad you are not oblivious and didn't notice it
