[lovespandp]

I would not put a muzzle on him. A muzzle is not a training tool. A muzzle will not teach him anything.

When he is loose, is he outside? When outside, you should always have the leash on especially if you are training him not to pick up things. You will have to work with him when you are inside as well… make sure you puppy proof your house, then leave something on the ground that would be safe for him to grab, but something you do not want him to have… When he grabs it, tell him Drop it. When he drops it reward him. You will have to do this consistent to teach him to “drop” things that he shouldn't have.