So our little girl Hot-Lips has come down with a cold.She's congested with leaky eyes. We have had her for a month and a half now. We kept her and the other chickens she came with in quarantine for a month before we integrated them in with our flock. No signs of illness in anyone else. It did not come on fast, rather a slow progression over the last week and a half. She started by breathing with her mouth open a bit and slowly started feeling worse. Today was the first day she was visibly sick. Again, there is NO signs or symptoms being displayed by anyone else. I would like to treat the whole flock with antibiotics asap. Any recommendations?