We adopted a pup (about 1 yr old) from a shelter. He was still very mouthy at that age. That really upset my daughter, so we had to stop it ASAP.
Every time he mouthed me, no matter how hard, I told him "no bite" in a firm voice and gave him a toy instead. If he played with that, I told him good boy over and over. If he persisted in biting me, I put him down. If he persisted after that, I put him in his crate for a bit.
Persistence, consistency, patience, persistence, consistency, and more patience is the only way I know to break this habit without affecting their bond or making them fearful.
__________________ Mario  was adopted May 2015. Now he is a service dog and brother to Bailey the Airdale mix  |