Wow, what a tricky bird! At first I was going to vote pullet, but after reading the other replies and looking more closely at the pics, I'm going to go with roo... tentatively. Its tail seems off for a pullet - stubbier, like its still waiting for the long feathers to grow in; the shoulder areas of its wings look a little darker to me, and its hackle feathers look long and thin in one of the pics.
Keep us updated!
Keep us updated!