Its always amazes me how little differences can effect a retriever. Probably 25 yrs ago I had a brute of a male chessy. His first shot waterfowl retrieves were woddys. He had retrieved doves and crows earlier in the fall and had retrieved pigeons and shackled mallards prior to hunting. Along comes the point in season where we can shoot blk. ducks and after a few mallards he was sent to retrieve a floating blk. duck. Soon as he grabbed it he spit it out. Fortunately he had been taught the hold command and he did grab it on command. Never a problem w/.ducks after that but never could get him to reliably retrieve field shot Canada geese or snows. He would retrieve geese on water but soon as he hit land they were dropped. Never did force fetch ol jake but you better believe when his replacement came along and he was retired it was force fetched and all since then. It does make a difference in even the best of em.