Chick did not feather on neck and grew mass on neck

[Chicky Poo]

Can someone please help me? I hatched this Wyandotte myself along with a few others. She never grew in feathers on her neck, not even pin feathers. I thought it was feather picking, so I quarantined her. It makes almost 1 month alone, and still no feathers. Over the weekend, she rapidly developed a growth on her neck. Tonight she died. I checked her for lice, but was totally clean. Her eyes were normal and clear. Was walking normal this morning and chirping.

 

[Chick Charm]

She may have died of asphyxiation due to the size of that lump. I don't know what it is. Could it be something that lodged in the throat before the crop and then got infected? Maybe cutting it open to see will answer some questions.

Wish I had an answer for ya but I don't.

 

[Chicky Poo]

I'm too chicken to open her up

Her siblings are totally healthy and thriving.