Our cats spend night times in the conservatory, they have a cat flap so can come and go as they please but other cats are now constantly coming in and spraying everywhere 
I'm thinking of losing the cat flap and letting the cats in and out of the house during the day and at night putting them outside but with a decent cat shelter to sleep in, preferably a heated one.
Does anyone use one that they could recommend or will it be horrible for them?(our conservatory isn't heated so does get pretty cold but they have a heated pad to sleep on). I only want to do it if they can be comfortable overnight in an outdoor shelter.