Is this flystrike or something else

[Barneycrew]

We've had chickens for a few years. This is the first time I've see anything like this. My older teen birds usually take care of the chickens and one of them brought "roadrunner" over the other day concerned with a goiter looking thing on the side of her neck. Then under one of her weeks is a hard crusty type wound the size of a golf ball. It is like a big scab. Could use some help on what to do and what it is. Is this flystrike? Seems that usually happens by their vent.

 

[Eggcessive]

Flystrike is when maggot larvae laid by flies, infect a wound or the soiled vent in animals and birds. That crusty swollen area could be an ingrown feather cyst full of pus, or it could be a type of skin cancer called squamous cell carcinoma. If you clean it well, and decide to probe it with a lance or needle, you may be able to tell which it is.