My horse's sheet has only helped him. He seems more comfortable with it on when its colder, especially if its raining. If I feel under the sheet he's always toasty warm! I do understand the arguement about smashing down hairs, but my boy doesn't really have many hairs to smash down

, his winter coat isn't much longer than his summer coat, and his summer coat resembles a show coat

. He does get cold if I don't keep a sheet on him in the 40's. He doesn't shiver but will put his butt to the wind and just stand there with his head bowed.