I might have forgotten to mention it but I also have a grey flight. Yes, I don't favour the greys, let alone grey greens but sometimes you just have to look at quality before colour when obtaining new stock.
Anyway, it used to be filled with a grey cock split ino and two grey hens. They were all new birds from last year. I really should take a picture of those three because they all have a different shade of grey. The cock has bred me a few decent greys, the hens haven't bred this season so I threw them in a flight this spring to see if they would start breeding. The hens didn't seem interested and neither was the cock.
I threw in the young grey cocks once they moulted through. In the main flight there was a decent grey cinnamon pied hen that seemed in condition. Also one I obtained last year and also hasn't bred yet (she was paired up to an ageing cock but all infertile eggs). Supposedly a sister of a hen that bred me one of my best cocks. She's a bit the odd one out as she is not a pure grey in the grey flight.
When this hen started showing some interest in the box I removed all cocks except the old cock and the best young son. She paired up with the young cock (~9 months old) and now has 2 eggs of which one certainly is fertile!