If the day old chick has them that badly already, you must have a pretty bad infestation

I would dust all your birds, including the chicks, with Sevin dust or permethrin (not permethrin if you have cats since permethrin WILL kill them) and also I would treat them with ivermectin for a double whammy (don't ivermectin the chicks, only the adults). Then you'll want to clean out all the coops and dust them down really well too. If you can use permethrin, Gordon's spray is really good for that purpose. If not, Sevin will work.
Then you'll need to repeat it all again in ten days to get the new ones that have hatched. You also might want to put Sevin/Permethrin in their dust bathing spots, so that they'll also be treating themselves when they dust bathe.