I have six chicks 10-12 weeks old, one week ago I heard strange sound from coop on morning release, labored breathing from one chick. Treated all six with garlic and apple cider vinegar in water, fresh cut herbs from garden in their food, and vet rx at night. The strange sound disappeared until this morning, I heard it again. I have been changing their water daily, and fresh food. They have free range of back yard in daytime, and good ventilation at night. I don't know what to do. They have all had hoarse sounding chirps and I'm afraid they will die.