Welcome to BYC. They have already been setting for 2 weeks it will take another 3 weeks for eggs to hatch. If you give them eggs, watch them carefully to be sure they do not lose too much weight or become mite infested. Brooding can be debilitating for some overly dedicated birds. I have had birds raise as many as 5 broods of chicks in a year and others only 1 brood a year. Broodiness varies greatly from breed to breed and bird to bird within breeds.
and Welcome to Backyard Chickens.
