I have always trained my own retrievers but have run into a problem that I haven't yet figured out. Any help will be appreciated. She is 14 months old and loves to retrieve dummies and anything I ask her to until a couple weeks ago. She then started going after the birds like always and then pouncing on the bird and digging at them so vigorously that she tears them apart with her claws. She does this with fresh killed birds, dead birds or frozen ones and does not pick them up. She is still very enthusiastic about dummies or going out to the birds. She has not been worked on anything except dummies, pigeons and ducks.