why is my 5 month old drake chasing away just one of my 14 duck hens, he won’t let her eat. all the other 13 hens he is nice to them all. he is my only drake. he has 6 girlfriends that are olds ladies ( (9 yo))and 8 that are young ladies between (5 mo & 2 yo) the one that he chases away is a white layer and I have another white layer that looks almost identical, but he can tell the difference