It sounds very much to me like it hasn't been refridgerated since they picked it up, and it's been left sweating in that bag, hence the fact that it's probably gone rancid. All the best!

my GSD likes em the mankier the better - i took her to the vet beause who breath smelt real bad and was told to discourage her burying them or put up with the bad breath - but the vet thought a dogs stomach should be able to take a bone that seems to have gone totally off

I've been told that marrow bones are too hard for dogs to eat? Like cow leg bones.

I wouldn't worry about it being 'ripe' but keep an eye on your dog's teeth in case it's too hard.

Marrow bones ARE cow leg bones, at least they are where I live! I have not heard anything about them being unsuitable though.
My late mother who had gundogs always held the theory that giving marrowbones to dogs kept their teeth clean through gnawing and it seems to work for mine; I check their teeth regularly. My lab friend is of the same opinion (she is also of senior years) and neither of us would dream of the modern idea of cleaning their teeth with a toothbrush!
The only case I heard of a dog losing teeth through having something too hard was a lab bitch who used to retrieve stones and bricks, much to the consternation of her owner
Maybe someone else has had a different experience?

I've only heard of a dog getting a tooth stuck in one? Maybe some of it splintered but not fully, and the dog got it's tooth stuck underneath it? I can't remember any more about it only that I heard of it.

I think when they bury them, they dry out, and I'm sure there's a reason behind the fact that they do this, maybe it also kills off any bacteria in them?

I would never feed rank meat to any of my dogs, nor would I feed a smelly rank marrow bone, only a nice fresh new one that I'd just seen cut in half. It's all too risky with raw for my liking, but then again, I've done too many health and hygeine courses in my time to know why!

Well we didn't have any side effects really. Well apart from her waking up as a teenager today and behaving like one for all of the time, apart from when we were out on walks.

SHe got on the sofa 8 times, was constantly trying to mouth me and trying to chase the cat. She is usualy such as angel.....she was perfect while out walking though.

She's teething and i think that was hurting her today - no idea why she had so much energy though....thought energy levels increased slowly, not over night!

I chose a marrow bone so that she couldn't eat it, i had been giving her bones she could eat but she became constipated. I spoke to the vet and she said to avoid giving her bones she could eat due to possible health risks like perforated bowl, empacted gut etc... i know i have been told that years ago but thought they might have changed their views now.

Anyway - hence the marrow bone. So the short answer is that i dont think the bone was off!

Thank you for all your replies!