Birds of a feather.....

[clothmama]

I don't know about yours but my hens can turn their heads around far enough to preen 90% of their bodies. That is enough to give them an idea what colour they are.

Yes mine too!

Yeah, I get that but whilst folk have pointed out the obvious colour thing, nobody has explained how they seem to pair up with the same breed, which was part of my OP.

I've never seen this so much as I've never bought in any hens other than my first 3 layers and the 2 silkies as broodies (then bought eggs). I find that each hatch stick together rather than colours, may be different if my flock was smaller / less groups of different ages.

[FrenchForumSurvivor]

We have a black cross breed cou nu which, neck apart is pretty much identical to the now, two other black hens who don't seem to have anything to do with it but have quickly struck up a 'friendship' with each other.

The Cou Clucks Clan are very discriminating.

[mysty]

Not sure about choocks but we have mirrors in the house and démon has been making avances to billy the cat Who has a willy.
I am sure if we had chooks he would hump them as well.

[TriciaF]

We had a pair of ducks who stayed on the pond all night, wouldn't go in the shed.
One morning the poor male was left alone - fox must have got his wife. He was very sad for a few days.
But eventually took up with one of the hens, and tried to mate with her which offended her cockerel.
They had a fight.
So like human behaviour.
I looked up whether a duck/hen combination could produce young and it said no.

[clothmama]

I looked up whether a duck/hen combination could produce young and it said no.

It can also be very dangerous for hens, when they mate the roo just squirts a bit of you know what on the outside of the vent. Ducks have a very alarming looking corkscrew willy and if they manage to get it in a hen can kill her. Shouldn't be kept as a lone duck with hens.