Feral female cat with little lumps on her ears and little bald bloody patches on her head.

[Fishstix]

She's not ours, and we can't have cats (son allergic) but she is a beautiful and quite affectionate thing and I hate to see her with an obvious issue. I don't think we'd get her to the vet, but she will allow me to pet her fit he kids aren't around so I think I'd be able to get something on her scalp or in her ears (she shakes her head a lot and scratches outside her ears a great deal).
We wouldn't take her to cat refuge as she is VERY much an outdoor cat and she is otherwise very healthy and happy playing around the farm and keeping the local rabbit and rat population on their paws. I think she'd be miserable stuck in someone's house, I'd just like to get her some meds to clear this up.

Anyone know what it may be?

It sounds as if she's got a bad ear mite infection - and I'm guessing that she'll probably have the lot, fleas, mites, worms etc etc. Poor girl must be miserable.

I'm also guessing that she's not been neutered and that could also be dangerous for her if she's a feral trying to feed and rear lots of litters of kittens over what would (likely) be a fairly short life for her.

Is there any chance that you could trap her humanely and have her vetted and spayed? CPL will usually help in this regard, particularly as she has a place to go back to. It would be awful if you had scads of likely infected and sick kittens all over the place for years to come. (Themselves breeding at an early age and compounding the problem.)

She's been neutered... I think she was a farm cat when the previous owners were here and they didn't want kittens all over the place. I flea treat and worm her with the rest of our livestock so she's in good shape apart from this. Will get something for ear mites, thanks for the suggestion.

That's a majority of good news then. Maybe give the vet a phone about the ear mites just to check whether they are prepared to treat 'in absentia'. (Not all would.)

What colour are her ears? If they are white it could be skin cancer unfortunately.

They are black lone cat. Phew!