I have an 86 year old spur thigh I adopted 6 weeks ago. The vet said is was fat as he forsnt stop eating but hes really slowed down the past week as temps here in Kent UK have dropped, hes not been hibernated for years so over wintering him with uva uvb lamps and ceramic heat bulb at night temps seem fine and I'm soaking g regularly but the past 2 days he hasnt eaten, hes pooping and weeing ok  is this normal, should I be worried? How long should I leave hom without earing before vets?