I just purchased an adult Rhode Island Red hen two days ago. I checked her out before purchasing I didn't notice anything wrong with her. When I got her home I noticed she was extremely congested and coughing occasionally. I've had her in a cage by herself and on a broad spectrum anti-biotic for about 48 hours and she's still sounding congested. Her poop looks good and there's no discharge out of the beak, and she's eating and drinking well. I'm new to chickens but I have raise smaller birds for years. Could this be a cold or flu? and are they common for chickens? What else could be done for her? I was thinking of putting a heat lamp on her but haven't yet. Any advice anyone would have would be appreciated. Thanks in advance!