What do you think??? have any winter tips??

It's not good to feed horses supplements if a vet says that they don't need it b/c they can get really sick from having too much of a certain vitamin. If you're worrying about him during the winter, get him a really thick t/o blanket and keep him in at night. Also you can see if you can feed him a little bit of corn or something like that because that makes them really warm and it gives them energy - just be careful that you don't give him too much and ask your vet first. Also he's going to need to gain muscle too, so keep exercising him in the winter (walking/trotting up and down hills is probably the best thing to build muscle m without tiring him out.) Good luck! :)