I posted a couple of weeks ago about what appears to be congestion in one of my eight young hens. It hasn't gotten any worse and there are no visible signs, e.g. mucus, swelling, sneezing, etc. but I can still hear her at night on her roost. It's like a rattle in her chest. She's a good layer and appears healthy and energetic but I was considering treating her with terramycin or duramycin but I see so many confusing and contradictory comments on how much to use, mg to tbsp conversion, CRD, virus vs bacteria, and eating the eggs while the chickens are being treated. Is there any anecdotal info about what I've described? Anyone want to share?