How are you asking for the foot? Has he been taught to lift his foot (this may sound obvious, but it is surprising how many people just assume the horse knows how to do what they are asking when the horse has not, in fact, ever been taught what is expected of them - leads to frustration for horse and human)
Since you mention you are renting the horse - have you spoken with the horses owner/trainer and asked for some additional work with them, yourself and the horse to perfect your asking? If the horse knows what is being asked and is not complying you are either not asking correctly for this horse or the horse has a general sense that he does not have any need to listen to any requests you make of him.
I had this issue. I don't think I can help, because this answer might be odd, but I changed farriers & went barefoot at the same time. When I bought smokie, the guy I bought him from picked a hoof up, and he leans ALL his weight on him. He never did that to me, but when he would give me his hoof, he would decide to take it away and slam it down, or he wouldn't give it at all. Now for some reason, he'll give it and not take it away until I give it back. I don't know if it's the farrier (who is awesome) or the barefoot but those are the only 2 changes Posted via Mobile Device