A couple weeks ago, I posted some pics of one of my girls trying to figure out what breed she was. Almost everyone said that she looked like a Buff Orpington. However, today I noticed that her tail feathers are now growing in a Dark Brownish-Black color. I thought that BO's were a solid buff color. She's almost 5 months old now, so I was pretty surprised to see the color of her feathers changing now. Any ideas what she might be?
You can't see the darker colored feathers in this picture, but it covers the outside 3 layers of her tail feathers.

You can't see the darker colored feathers in this picture, but it covers the outside 3 layers of her tail feathers.