I have a gold sex link that is coughing and sneezing. She started this about 3 weeks ago when we brought them home. Thinking they might all get sick, I gave them Agrimycin-343 in their water. She ceased the behavior almost immediately. Last night... it came back. I have again redosed with the agrimycin. I have not found any poop that looks out of the ordinary. (they are free ranging though). I am using pine shavings for bedding and pine shavings and oat or barley straw for nest boxes. Is she alergic to something? Is there something else I should be giving her? Is this a normal thing even?