Hi! Our choc lab Charlie (almost 2 years old) knows the 'leave it' command well but he chooses when he wants to obey it. Especially with food. If we're on a walk and he see's food on the ground before I do, he will gobble it up and despite me saying 'leave it' he will ignore me. I have to physically pull him away and then try to get whatever's in his mouth out. Is there anything we can do with his training to help stop this?