Me again, have you got a vitamin / electrolyte solution to put in their water? If you don't have a poultry electrolyte, use 25 % human liquid electrolyte in their water and crush up a multi vitamin or, vitamin b in the water
Have they been dusted? Put polysporin on their feet and legs and beaks and combs. Wash before you go in to see your chickens. Ask a vet about the anti biotic, All antibiotics do not resolve respiratory problems. Good luck