Lumps/sacks/growth on tail bone

[WangoTango]

My older hen has lumps/skin sacks/growths/tumors on top of her tail bone/back area. Does anyone recognize this?
The only reason I noticed is because she started molting and this exposed the area.
She does not weigh less, eat less, or move less. Perfectly normal behavior. She does not react when the lumps are touched. She was recently broody and I was carrying her out of the coop into the field daily for a few weeks, so I've had a lot of interaction with her lately and nothing has seemed wrong until finding this today.

 

[MysteryChicken]

My older hen has lumps/skin sacks/growths/tumors on top of her tail bone/back area. Does anyone recognize this?
The only reason I noticed is because she started molting and this exposed the area.
She does not weigh less, eat less, or move less. Perfectly normal behavior. She does not react when the lumps are touched. She was recently broody and I was carrying her out of the coop into the field daily for a few weeks, so I've had a lot of interaction with her lately and nothing has seemed wrong until finding this today.

Ingrown Feathers.

 

[Wyorp Rock]

Hard to see the oil gland in the photos, do you see it? Does it look o.k.?

 

[WangoTango]

Update: The vet didn't want to cut into the lumps, suspecting they are cancer/tumor related. She prescribed oral antibiotics just in case but said they probably aren't infection-related.
Lumps are still there weeks later. Feathers grown back. She has never acted anything other than fine, so I don't know what to make of it. We'll just keep on keepin on. Thx!