I recently changed barns and am now "on my own" so far as feeding my horse.  The previous barn I was at he lived in a field (not much grass at all) and had access to an alfalfa bale.  He was not fed any grain.  He did gain weight when I purchased him and brought him there and at the previous owners farm was on grain once or twice daily and had access to hundreds of acres of great pasture.  Now that we are at the new place he has lost weight and I am increasing his grain since the pasture has died for winter.  I also feed him alfalfa cubes in addition to the grain.  I have been told by my previous trainer that he is too thin but those at my new barn say he is fine.  I did check a body condition scale and to me he seemed to rate at a four but I am used to the old farm where all the horses were very round and sometimes called fat.  I board with a vet and she thinks he is fine but I still feel his too thin for my liking.  Any suggestions?