My male duck ( Royen ) atacking one of the female ducks

[Ursuline Chick]

He may not "like" her and not want to mate with her. Or she may not want to mate with him. Long ago, when we had a full size Rooster, and we had a hen who just was not interested in mating with him. She wouldn't squat for him and he would just grab her by the neck feathers and try to mount. She would start running, rooster holding on to her neck for dear life as she flung him around the yard. He had 11 other girls to pick from and he did (I believe) service them all. Except this hen who hated him, and he kept trying, and she never relented.
It was funny to watch, as the poor rooster was all but flying behind the hen. But sad as well, as she continued to reject him. He was a beautiful boy, big waddles and the whole nine yards, real looker.

 

[Manuela M]

He may not "like" her and not want to mate with her. Or she may not want to mate with him. Long ago, when we had a full size Rooster, and we had a hen who just was not interested in mating with him. She wouldn't squat for him and he would just grab her by the neck feathers and try to mount. She would start running, rooster holding on to her neck for dear life as she flung him around the yard. He had 11 other girls to pick from and he did (I believe) service them all. Except this hen who hated him, and he kept trying, and she never relented.
It was funny to watch, as the poor rooster was all but flying behind the hen. But sad as well, as she continued to reject him. He was a beautiful boy, big waddles and the whole nine yards, real looker.

Yeah, but this looks different then wanting to mate. He just doesn't tolerate her near. As soon as she comes close and he sees her - chases her away or just makes few steps towards her like he wants to attack and stops but she runs off.So far she is not hurt. I think it's a little better today.

 

[Ursuline Chick]

It sounds like he may not like her for some reason. Have you checked her to make sure she is not sick or injured and just hiding it?

 

[Manuela M]

It sounds like he may not like her for some reason. Have you checked her to make sure she is not sick or injured and just hiding it?

She doesn't look sick or injured but I will take a second look tomorrow.

 

[Anime2lover]

Hormones can get the best of them. How many females do you have? My Runner drake will make a move to keep my fawn and white Runner at a distance he doesn't attack her just uses his bill to let her know he doesn't want her around. Hopefully giving him some time out will get him under control. Are all your ducks Rouen? because sometimes a drake will pick on a duck that isn't the same color as the rest too for some strange reason.

It's pretty much a wild left over instinct that some show and others don't. A duck that is to different will likely easily attract more preds. That's why a lot of prey animals look very similar to one another. Same with the different duck species (with some exceptions)

It sounds like he may not like her for some reason. Have you checked her to make sure she is not sick or injured and just hiding it?

She doesn't look sick or injured but I will take a second look tomorrow.

I agree with @Ursuline Chick you should definitely check her over.

 

[Ursuline Chick]

I hate to keep saying it, but he may just not like her for some reason. Is her coloring a little different than the other girls, or is there some small thing she does or about her appearance that could make him be disinterested in her?

 

[Manuela M]

I hate to keep saying it, but he may just not like her for some reason. Is her coloring a little different than the other girls, or is there some small thing she does or about her appearance that could make him be disinterested in her?

Well her tail feather is slightly curled to the right . Thats her trade mark. Everything else is same as the others . Only she is the only one that never liked to be cuddled and picked up. But she has always been like that ( 9 months ). Why is he upset about it now ?

 

[Ursuline Chick]

Hormones, testosterone poisoning
Perhaps the feather gets in the way of his penis when mating