one of my duck gets run off by the other ducks.

I have four ducks. Two of them are male, and they are Pekins. I have two females, one, I believe is a Cayuga, the other duck is a Mallard.
Recently, I started to get one egg a day, at that point, I started to notice that the males are running off the Malllard. They mate with her a bit, but mostly run her off from the water bowl. They also run her off the pond for no reason. They run her out of the water and halfway up the pasture, too. I have not noticed any feathers missing, and they aren't pecking at her, unless they are trying to mate.
I am new to ducks. I have had these guys for almost a year, they are about a year soon, as well.
The males seem to be doing most of the running off. I am not sure if it is the same male every time or not, cause I usually see one do it at a time and I can't tell them apart.
If anyone has some advice, I am all ears.
Thanks so much.