I am new to raising chickens. I have 6 hens, 2 Rhode Island Reds, 2 Buff Orpingtons, and 2 Buckeyes or so I think. All are healthy looking except for 2 of them. One of my Buffs is a runt compared to the rest of flock and has no sickles extending from rump. Is this a defect in her breeding? And will she lay eggs? She is about 24 weeks old or so I think.