Well I admittedly kind of glazed over the fact the original poster was talking about an elderly bird.
Well...
THAT CHANGES EVERYTHING.
That bird needs a diaper, a permanate hand carved solid oak roost in front of the fireplace and three gourmet meals a day approved by chef Ramsay.

Yeah I'm sure as they get older the coldest probably harder on them.
Just like it is us.
But I still stand by my opinion that it will be even that much harder if something were to come up where the heat source was unavailable once the bird got used to having it.