My dd's white rat is sick - it's 18 months old. Sitting miserably alone, sort of fluffed up looking, and breathing very heavily, sides sinking in deeply. Eyes half open. I've scrubbed out the cage in case there were mites, and I persuaded her to eat some yoghurt. Only have shredded paper as bedding, so not cedar or pine or anything harmful. We don't have access to a small animal vet here (rat is a rehomed 'feeder' 
rather than a proper fancy rat). Anyone have any ideas what I can do? Greatly appreciated...