All roosters have curled tails when they grow older, unless they're rumpless, like Aracaunas. There's not any specified tail shapes in chickens. Your cockerel is just young, and his feathers haven't grown our yet. You can tell they're starting to get curved.
Dont know exactly how to say in english but we say good day is seen in morning so i just dont like roosters with simple tails and straight
I think you're asking if he'll have a flowing tail as opposed to a more modest tail? It looks like his tail will trend towards the modest side in my opinion, similar to the photo below. Cheers!
