We live in Alberta, Canada where we get very cold winters. This is my 1st winter with my new horse. I have been told that a winter blanket on ahorse can really affect their winter coat that helps to keep them warm by flattening their coat. Today it rained quite a bit around here so my horse is quite wet (he has a shelter but chose not to use it). I am concerned for him a it is a bit chilly out. I do not own a rain sheet but I am wondering if I should purchase one?! Should I be putting one on him? He is getting his winter coat and is already quite fuzzy. If I put a rain sheet on him will it flatten his winter coat and hinder him during the winter? I was not planning on putting a blanket on him over winter as he has gone through winters in the past without one. If I do get him one what size should I get...he is a standarbred gelding who stands 15.3 hands.