It won't hurt them, but treating lice is an ongoing situation as the eggs are stuck on the chicken, so you're going to have them hatching for a couple weeks. The issue I would have is lice possibly getting on the chicks, as something that small can suffer blood loss quicker than a grown bird.
I would treat all of your hens with something like permethrin powder for lice, not DE powder. And strip the coop, etc. Personally, I'd put the eggs in an incubator too.