I didn't know there was such a thing either. However, I picked up some White Silkies from Tractor Supply just because there was only 9 left and they were destined for the trash can at closing in about 20 minutes. They were pitiful looking. Well, my wife and I's Christian hearts just couldn't let that happen to them so we bought all 9 even though we knew we may loose 'em. Next couple of days we lost 3 and we saved 6. As of July 1st 2017 they are 12 weeks old. 1 is Bantam size, the other 5 are larger then my Black Sex links that are 16 weeks old and they are tough as nails. So much for being docile. When I go in the coop 2 attack me and try to chomp on me like I'm corn on the cob. I think they're great though. Definitely some of my favorites. Here's a pic of 'em with a Black Sex link who is 4 weeks older. They're not Bantam size.