they are probably too hot!
You've seen the ready-brek advert "central 'eating?" well, the oats will be keeping their body temperature up, so they may be feather plucking to cool down.
or they are moulting.
maybe a course of anitbiotics would help with the respiritory problem? it could be any number of things, maybe call your vet or search t'internet abit to see which symptoms match the closest