In breeds with long tails, they should be longer than that. My own longtails are not exactly 100% pure however even they as chicks at that age obviously have "looks long" tails even if they don't have full tail length at that age.
I already explained why brown leghorn or phoenix are probably not good guesses- it's not strictly the tail.
I already explained why brown leghorn or phoenix are probably not good guesses- it's not strictly the tail.