[Aunt Sally]

Little 6 stone lady and Sumo Wrestler.  Hmmm... doesn't sound like a good match to me 

Why do you allow it ?

[Pretty Chick]

I don't anymore he is to be separated from them at all times during the day, but I will continue to put him in the house with them at night.

[joyfull]

I'm not sure Pekins have Joyfull (I think you meant Polish).

thats the ones, those with the funny hairdo's 

[woodburner]

I had a silkie in with my big girls and boys for a while, but she was so quick, she rarely got trod, to the point that her eggs stopped being fertile!
For a while I had a young cockerel who would just stand on the hens, like a hunter with his kill. If your boy does this, I could well imagine him suffocating a bantam.

I'm a bit puzzled, by your description of his behaviour.

We see the cockerel attacking the hens every time he can get to them.

When he's let out in the morning, my boy chases the girls and grabs by the back of the head, usually managing to hold onto one and mating her. He then leaves them alone, presumably he catches the rest at some time during the day, but I don't often 'catch him in the act', he certainly doesn't persist in chasing them, and they never fight like cockerels do with each other.

Are you preventing yours from mating, so he remains frustrated or something? 

[8doubles]

The answer may be to have some low cover that the hens can get under so they are not molested by a rampant cockerel.

[Pretty Chick]

We don't let him mate with them anymore because he just kept on which made the girls unhappy.
When we allowed them to mate, he seemed pretty happy and had no reason to keep on.
He seems okay at the moment, even though he isn't with them during the day, but the minuite he is let out in the morning, he goes for one and that is the time we separate him.

[woodburner]

I've been reading bad things about Orp's mating habits. Most normal cockerels would be happy with 8 LF hens, (have I got that right?) and 9 banties! My LS boy is happy with his 8 ladies, though when there were only 3 he was too much for them, (backs worn bare).
If you don't want him to breed Orpies with, and you can't run him with the hens to look after them etc., I think it's time to part company with him. I strongly suspect that most of the time the banties managed to keep out of his way, but when he did get to them, he stayed standing on them after he had done his business, and they suffocated. 
You could keep him permanently penned up, but what would be the point? I was about to suggest keeping two seperate flocks, so that he has hens, but can't get to the bantams, but he's a pain to the LF girls too.
If he's good type, you might find a breeder that would take him as tbh I have heard of worse ones than him!!!

[TeaPots]

I had a stupid little cockie that would catch his wife, and just stand there, no fluttering around. He was only young, and had to be shooed off! He soon got the hang of it though.

 I also had an very ungentlemanly cream legbar...Bertie, who was so passionate, he managed to break the pelvis of his wife...she hadnt squatted ready, and he launched on her back when she wasnt prepared. He used to bite them by the throat t try and get them to stand still. He is no longer 'with us' now.

[dizzylizzie]

I have a beautiful maren cockerel who has 21 hens at his disposal. The smallest hen we have is a legbar, all the others are marens, warrens, barnies, orps...all big girls but all of them are thread bare, 2 of them are totally pink, the rest were getting there but we have put saddles on most of them now. He comes out of the coop in the morning and he is rampent!!! We put him in a run by himself till the 'urges' have worn off a bit. It gives the girls time to wake up and have a drink/something to eat, and he is calmer when we let him out. I wouldnt have him anywhere near banties though-im sure he would kill them
He is a sweetheart though, he looks after the girls, stops and squabbles, protects the chicks, finds food for the girls and helps new ones settle in. We have a bald ex-batt and he never touches her, maybe she dosent do it for him being bald and all!

[Pretty Chick]

Thank you for the advice everyone, but we will never get rid of him.
We have three large cages for the chickens and he is shut in one of them. His cage's dimensions are 4 metres by 4 metres and height= at least 2.5metres (and that's the smallest cage!) so he's not squashed into a little pen or something like that.
He is quite happy to be on his own (he hangs back in the mornings while the girls come out of the hen house and into the garden, as he knows where he is wanted  )and we do sometimes let him out with the girls while we are watching.

Thanks again for all the advice given  :happy: