Help with my thoroughbred?

My horse Tory is finally back from Washington State. I had him checked by 3 vets and they said that i can slowly start jumping him. I started working with him and noticed that every time after our workout that his hocks are very hot. Should i be worried? Could it just be from the boots or could the work out be hurting him? He is walking normal, not showing any signs of laminitis and my vet said its normal. My dad said that its not normal and i should give him alittle extra time to recoperate. I'm not sure what to do.. Helpp?