I won one time! You just have to make a 'My Chickens' page here and post a link to your page in the thread linked to at the beginning of this post. I'm not sure if you have to post a link to your page in that thread or if they will look through all of the chicken pages but better safe then sorry. I'd go ahead and put a link in there.
Good luck!
PS I assume you know but just in case I'll say so anyway: it's chosen by the people who run the site not by vote.