wyandotte question

[chicken long]

I have a flock of assorted wyandottes. They are almost 8 months old and they all still have the fluffy down feathers on their lower back just at the base of the tail feathers. Is this normal and when will their hard feathers come in. I have had thru the years many breeds of chickens and this characteristic is new to me. Is this normal or is there a problem?
Thanks, Bill

 

[NanaKat]

Could you post a photo?