What is with these tail feathers?

[aim0474]

One of my production RIR hhas these strange tail feathers. I thought at first that they werent falling out when she atarted getting her big girl feathers. They arent budging though.

Thanks!

 

[Earl Medcalf]

Similar I have seen involves first chick feather set not being set / cease growing. The feather keeps growing even though it would normally be shed. During that period of extended growth the feather making tissue matures causing the more mature look of the subsequent feather set (first juvenile). Since the first set (chick feathers) are retained longer than usual, only the rachis persist thus looking as you see. Actual cause I do not know.