My Lab is almost three years old and has been force fetched. He will do good retrieves with a dummy, but put the bird in his mouth and his training goes away. I think some of it came from when he was almost a year old and we were hunting doves. He did a good job at first, but after a few birds he started refusing to retrieve or pick the bird up. So back to force fetching and retraining after that. I have never used him on doves since but still does the drop as he gets near a person. Generally finds birds well, flushes them and goes immdeiately to a downed bird, only won't continue to bring the bird in right to heal. I have had other dogs I've trained, and this is a first time habit for me which I can't get trained out of him. He will hold and fetch after he drops it and etc., but will not bring all the way into heal without a drop or two.