My rats have been on two medications for a upper respiratory infection for the past 10 days. Today is the first day off of the antibiotics & i notices one of my rats are breathing with his mouth slightly open. I've only had them for about a month & they are still young & getting used to me. My rat Puff is VERY timid & NEVER comes up to me unless i have a treat. Most of the time he's hiding or keeping his distance. Today i went to try to hand him a treat and he jumps onto my hand and starts sitting on my shoulder & just wanting to be in my hands in general. He seemed a bit weak or slower than usual. Does anyone know why this may be? He's been on antibiotics & i thought he'd be better by now. & i also don't understand the change in behavior.