I would be far more concerned about rabies than Covid. If the babies belong to that sick one, they could have rabies as well. I'd call your local game warden, fish and wildlife service, or whoever is in charge of wildlife in your area. (If they were near here, they would likely disappear.)
hopefully their ok, and will continue to leave the chickens be.

If you have other animals outside, though, I'd at least make sure they are all up on their shots.