I have an exracehorse who has spent 10 years more or less in the stable, he is 14 now and quite a toughy for a tb, i too leave him out as much as possible with hay and a feed even in the summer as he has been used to top quality forage all his life, i only bring him in if the weather is at its worst, he has constant grazing if he wants it, even though he did spend so much time indoors he has taken to his new outdoor life very well and touch wood no laminitis up to now !