It's not just a potential fire hazard it also acclimatizes animals to unrealistic temps.. this is an area that has to be handled carefully, to use larger livestock as an example a horse.. if you blanket one they simply don't grow the coat required to be without one, so you must use this the whole season of cold.. it really cannot be temporary unless it's only a brief few hours...
The biggest problem with birds is they are prey animals often hiding ailments, so when weather extremes strike it takes them down, you may never know the reasons why, i am not cruel i have brought in birds(heck even bigger livestock.. my lambs) but this is brief as the temps within my home are very opposite.
The strong survive, the weak do not. That is the bitter reality of raising livestock.