When my dogs do this I offer them a more appealing treat - the thing they love most And when they drop what they have in order to get the new treat I can either take it right then or I toss another piece of their favorite thing a slight bit away for me so that they turn to pick it up. My dogs are pretty good about give but every so often they will get some treasure they don't want to give up like a rabbit they killed in the backyard. And although one feels like throttling the little beasts, I have found it is much more productive to praise them to high heaven for being such good boys when they let go of the treasure