My two female chickens are about 18-20 weeks old and have not yet started to lay. A Black Star and a Goldline. They get on quite well but when one gets in the other's way they both leap up in the air with their feet forward and meet foot to foot. The contest is over in a second with no real fighting. I know that roos fight like that but I did not think that females did. Also the Black Star sometimes tries to stand on the Goldline's back. Is this normal or is it because their hormones are not working properly yet?