I'm needing some advice. The mare I lease has just started playing some sort of game with me during grooming. She does not want to pick up her front feet to be picked, and when she does, she will only let me pick them for about 10 seconds before she puts it back down. She does not do this for her owner, nor does she do it with her back hooves. She is shod, with pads on as well, if that makes a difference...thanks for any training advice you can give to get us past this!