I'm concerned about my society, Marshy (forum namesake).

- Marshy shortly after singing.
He is not digesting his seed properly, and the undigested
seeds are showing up in his poo. He is also spending most
of his time in the nest, one of the woven bamboo ones
from PetSmart. This has been going on for a few weeks

but he has given me no real reason to be ultra worried. He seems to be eating well, and digests at least some of it. But I'm really worrying. I can't get any medicine, or much of anything I don't already have. The only other finch in the rather large (for two birds) cage is a girl zebra.

- Cookie, Marshy's buddy.
She doesn't have the seeds in her poo. She also accompanies him in the nest, but spends a good deal of time hopping about and beeping. Sorry for the super long post. Marshy is my only hand tame bird, and I want him to be as happy and healthy as possible.

- I picked up a dried poo example for a better pic. (slightly gross, but I really don't mind)
Bad picture, but I've had to use my Blackberry.
The seeds are shelled by Marsh, but still undigested.
I want to help solve this, and I would like to know what could cause this. I can't really find anything on the internet, I get up really early and when I get home I have to do homework, among other things.
I also feel I'm underestimating this. Hopefully, but not probably, this is just me being paranoid.
Please help!