
Reckon the one on the right is a cock, middle one hen and furthest left possible hen too. If the 2 on the left are young, all bets are off though!
If you're looking to breed them, I found the best way was to literally throw a whole bunch of them in together with different coloured leg rings on and see what happens. I had 2 pairs for a whole season with no interest at all, got another 2 pairs and now I've got 3 pairs breeding this season. So, space permitting, go for it!