I saw something similar on a Newfie pups elbow, it grew to the size of an orange & flopped about. The pup wasn't bothered, the vet said it was just fluid and in time it went down.

Have your vets put a needle in it? How is it possible for so many experts to come up with 'nothing'?

Neither vet wanted to put a needle in it. Just pressure wraps and antibiotics. One leg had gotten back to normal size so I removed the wrap and it swelled back up within a couple of hours. The other leg is still wrapped. I also had 3 vets/vet techs look at her at a dog show my aunt was showing at. All had different theories. Just gonna give it some time and see what happens. No, we don't have dog insurance. Either way, I have taken her to 2 vets and paid out of pocket. Having insurance won't cure her.

I'm really surprised both vets didn't want to take a sample. Did they give a reason why? It's obviously something that needs to be addressed by a vet since it swelled back up soon after the wrap was removed.

What did the vets/vet techs have to say at the dog show think?

Can you take the pup somewhere else?