Pecking order

Hi from a new member but old keeper of (young) hens.
Having bought 2 local Marans POL and 2 speckledies POL from Wales
for my back garden, all laying well, I was surprised by not only was one
of the Marans 'treading' both speckledies but is trying its best to crow like a cockerel.
The other Marans won't be treaded and has fights and 'face offs' with (She-He-ila)
The Marans are quite larger and more 'Butch' than the Speckledies.
Its like keeping two ugly sisters and two Cinderellas 
Has any other member had this amount of 'pecking order'?
I'm wondering wether or not to seperate him/her for a while

Hi ICE,
Thanks for your reply, I followed the thread you sent and was relieved to find
I'm not alone with this situation. Will keep an eye on 'Sheheila'. A thought crossed
my mind whether or not to borrow a local cockerell to put her in her place.
(In the kitchen) tee hee hope my oh doesn't see this.
Will try and get some pics together, regards Derculees