He started getting these feathers around 6 months old. before that he was all green like a standard alexandrine, he's about 15 months old now.
I wouldn't think it's a health thing, he eats a good mixed diet of fresh veggies and pellets and the yellow feathers consistently grow back yellow after molting.
I wish he wouldn't always chew off his tail feathers though, although it probably makes it easier for him to fly inside my apt.
Thanks! tango's a great little guy. good talker too, started talking around 6 months. I'm a big fan of your guys birds too. If you haven't seen it check out my other thread "Tango Meets African Grey", thats my favorite pic of the lil featherhead.