6 week old chick with lumpy and scabby neck and head

[LaCosecha]

Hi everyone, I'm new to having chickens and everything has gone well so far except for this girl.
She is a mystic onyx which I understand has some Silkie in it. She has always been a bit of a lone ranger but ever since about the 4 week mark she has slowly developed scabby, bumpy, and flakey skin on her neck and head. Her feathers are growing in much slower than the rest as well, basically everyone is feathered out but her.
I've spent long hours watching them and haven't witnessed any bullying or pecking. She is still eating and drinking and doing all the normal chicken things, but whatever is happening with her skin looks painful. I'm thinking it could be allergies as I have recently introduced them to the outdoors, maybe ingrown feathers or an infection of some sort? Thank you all in advance.

 

[ladybrasa]

If she were a cat or dog I’d wonder about food allergies or mange mites, but haven’t heard of those issues for chickens? Maybe fowl pox? Just throwing out a guess.

 

[ladybrasa]

Maybe?
https://www.backyardchickens.com/threads/dry-scaly-face-and-comb.1144463/

 

[Eggcessive]

There is a type of Mareks symptoms that cause skin lesions. She is about as young as Mareks disease symptoms could occur. Was she vaccinated? Scaly face mites is another thing that comes to mind, especially in the second picture. Are there mosquitoes or any insects around. Where is she being raised, and what type of bedding? Can you look for any body mites or lice on her skin? Has she been scratching or getting pecked? Poor thing looks miserable.

 

[Eggcessive]

Have you had any other birds with favus or any similar white patches on the comb or scalp. Favus is a fungal infection.

 

[LaCosecha]

There is a type of Mareks symptoms that cause skin lesions. She is about as young as Mareks disease symptoms could occur. Was she vaccinated? Scaly face mites is another thing that comes to mind, especially in the second picture. Are there mosquitoes or any insects around. Where is she being raised, and what type of bedding? Can you look for any body mites or lice on her skin? Has she been scratching or getting pecked? Poor thing looks miserable.

She is inside in the brooder at night, and just recently going out to the run during the day. If I remember correctly, she had some scabs prior to her spending the days outside. The bedding is pine shavings. I haven't seen any mites on her, and none of the other chicks have symptoms either. Some of the photos of scaley mites do look similar, though!

 

[LaCosecha]

Have you had any other birds with favus or any similar white patches on the comb or scalp. Favus is a fungal infection.

No, she is with 4 other chicks and they are all healthy as far as I can tell.