depressed?

Question
How can you tell if you ferret is unhappy? I am sorry to admit that since getting Joi in November 06 we haven't been able to get her any other vaccines or take her to the vet since I lost my job, but we do out best to take care of her other than that. She seems ok for the most part, the kids and I are always playing with her, but sometimes she just sits staring out of her cage and "slides" around ... She has a large cage with 3 shelves, plenty of food and water, toys and a hanging tent... It gets cleaned at least every other day and thoroughly each weekend, unless my son forgets, but only twice has it gotten to the smelly point.
She's pretty much passed the nipping stage, though every so often she will, usually after being played with or held for awhile, and that's when we put her back in the cage.
Back to the point.. how do I know if she's really happy?

Answer
Well, you can't really know if an animal is "happy' but what you do want to see is "natural" behavior.  Check out anything on-line by Bob Church regarding enrichment to help you come up with novel ideas to keep your intelligent animal stimulated.  Usually the more intelligent the animal, the more work to keep them healthy.

On another note - you need to make sure your ferret is vaccinated.  Rabies is usually required by law and the animal could be confiscated.  Canine Distemper is fatal and very contagious and you can bring it into the house on your clothes if around an infected dog.  Be careful!  Some vets have clinics and will even vaccinate a ferret.  At least get a rabies shot!  If you have a chance, either pick up Ferrets Annual 2007 or the book Ferrets For Dummies.  The book can probably be found used or cheap somewhere!  The magazine is a great reference - maybe you could get a subscription to Ferrets magazine for a birthday or Easter!  Not too expensive.

Make sure your ferret gets plenty of daily play time out of the cage - 2 hours is recommended.  And find some good enrichment ideas.

As long as she is healthy and stimulated she should be fine.