if he;s stabled and losing weight first of all make sure he's getting enough fibre. Ideally, ad lib hay should be available, but it depends - if he puts on weight easily, this may need to be more tightly controlled. Ideally he shouldn't go more than 6 hours without some hay or feed - horses are designed to "trickle feed" all day and this is important to keep his gut flora working properly. His feed should be fine but if you find he's losing weight an excellent conditioning feed is alfa-a oil - its also really high fibre too so won't heat him up if he's a bit fizzy. You may want to try just a compound conditioning cube or mix instead. hope this helps you out!

thanks for your comment  i think he seems to loose weight easily in ther winter and we have to reduse the amou t of feed he is getting in the summer because he puts weight on easily. He isn't fizzy towards his feed he is just young and wants to play all the time so i hope this answers your question so you can hopefully answer mine