Wow! So many responses in such a short time! Looks like the consensus is a rooster!
Now I have to find a home for him before he starts crowing and the neighbours kick up a stink!
Thanks for your help everyone!
Here's our story:
Early November '09 I was given this chicken as a couple-week old chick.
A bloke at work rescued it from a cat, and long story short, we have had him/her as a pet.
Now, we've always assumed it was a hen, but recently, we're not so sure. In fact we're 80-90% sure it's a...