I have a litter of 6 pomeranian chihuahua mixed puppies they are 5 weeks old and one of them is unbalanced and falls over. What could be the causa of this?

Suggest you ask your vet that question!

We cant diagnose on line, nor can we suggest what this may be. To be on the safe side, have the pup diagnosed properly by a vet. NOW#

Sounds neurological, but that's just a guess, which is all we can do online. You're going to have to go to the vet, that's part of breeding, even as a backyard breeder you have to have money set aside if there are issues with the pups or the mom.

Since I'm not a Vet, How do his/her ears look? Infection?
Then take him/her to a vet. Good Luck

Since I'm not a Vet, How do his/her ears look? Infection?
Then take him/her to a vet. Good Luck
I am not a vet either, but have experience with pups. I would not necessarily say ears, but if eyes are runny, nose runny, sneezing, then it could be upper respiratory infection.

You MUST get this pup to a vet to be properly diagnosed.

For Sure