What is causes this?

[aprilgrem]

I have 3 chickens that are about 27 weeks old. Only one is having this issue. I started noticing that she was missing feathers and then yesterday I saw that she now has a huge bare spot! The other two are fine. I started spraying blue kote this week to hopefully keep the others from pecking her and started feeding them eggs this weekend for the extra protein. She is also the only one that isn't laying yet.

 

[Poultry parent]

looks like some sort of parasite

 

[aprilgrem]

looks like some sort of parasite

A parasite?? You mean like mites or something completely different? These are the first chickens I have ever had.

 

[Poultry parent]

yes. http://www.the-chicken-chick.com/2012/08/poultry-lice-and-mites-identification.html