One of my serama roos was having trouble breathing and his comb and wattles were bluish. There was no discharge and all of my other chickens were acting normal. I brought them in, gave him some injections of Baytril(just in case it was something) and he showed no improvement. I got this roo as an adult and he always had very long spurs so I thought maybe his heart was just giving out due to old age. I found him in a sleeping position yesterday and he had passed away. Well, today I found my littlest hen all puffed in the corner and she appeared to be breathing a bit heavier than usual. I grabbed her(and her sister for company) and brought them in the house immediately. I've started them all on tetracycline as I've read that's good for upper respiratory problems. What has me stumped is that there is no sound of congestion and no discharge of any kind. Is there something I'm missing as far as symptoms? Something I should be seeing that I'm not? Should I be using another antibiotic? I have access to inj. baytril, oral tetracycline, amoxi, doxycycline and cephalexin. The tiny one that is showing symptoms is still eating and is not thin.