I've read that roos feather out faster than hens! Also, how do you prevent the zip tie from closing and cutting off the foot?I raise blue black splash English Orpingtons and have a method which has proven to be VERY reliable. At exactly one week old, I look at their fuzzy butts. The boys have nice rounded fuzzy butts still covered in down and the girls have tail feather spouts. I throw a pink or a blue zip tie around their feet and sure enough I am right about 90 to 95 % of the time. Once that one week mark passes, it is impossible to tell... At that point you need to wait for combs and wattles.