Imprinting most always works, but they will always have certain instincts that will stay with them always or at least during their youth. Most of them get upset when when you hover over them because it mimics predators from above... Hawks, etc. You can work on this by approaching them from the side instead. They will be more inclined to build trust this way and eventually you should be able to hover over them without them freaking out. Often times they will even start lying real low as youwalk up, making themselves easy to pick up. Baby not following could be that imprint is being lost, or that he is just happy and confident enough to let you stray a bit.... Which is a good thing. If there are other animals around a lot.... Cats, dogs, ducks/ducklings... Then the imprint on you can be lost pretty quickly at this age.