I have a 5 year old Sheltie named WINSTON. He has a very full and flowing coat...but he is already so hot and it's only May. He spends most of the summer indoors b/c he can't handle the heat in Memphis. I have long heard that the undercoat keeps them cool but I can't fully buy that when I see him year in and year out - just worn out, tongue dragging b/c of the heat and humidity. He only gets out in the early morning for walks. I want to cut him way down for the summer ...thoughts??