Hi! I recently bought 2 more ducks to add to my group as my original 3 ducklings grew up to be 2 drakes and 1 duck. All 5 are close in age about 4 months. I'm surprised that the drakes are giving the new girls so much trouble. The drakes are chasing the new girls and biting their necks. Should I worry about this behavior? Is there a way to ease the transition? Thanks for your help!