Hi Dee
Well done on choosing a chipmunk for a pet, she's lucky to have a new owner that has put some time in doing the research first.
You don't give the size of your ferret cage, but they tend to be wider than they are tall. Chipmunks prefer height, the recommended minimum is said to be about a meter high and half a meter wide for one chipmunk. The more space you can give her the better, if you can give them a floor to ceiling high aviary it would be great. But if room is tight, letting her out of the avairy each day for a run around can compensate for a smaller aviary.
It can be tricky adding another chipmunk at a later date. Although they live in colonies, they still need their own territory within the colony. If you want them to share the same aviary you need to clean all the aviary before introducing a second chipmunk (territory is marked out with scent), and watch them both very closely after introduction. In groups they seldom play together or seem to need anothers presence, except for when they want to breed. Even siblings can squabble, and there is no way of knowing who will get on with who. Everyone who has groups seem to agree that only having one male per group of females works best.
I've written a page on the dry types of food they like to eat:
http://www.super-chipmunks.co.uk/dryfood.php I've yet to write the one of fresh food, but they do love fruit a lot. Grapes, apples, sweetcorn cherries and so on. If you give them peaches don't let them have the stones in them, something toxic in them. Also they love nuts, peanuts in their shells (monkey nuts) seem universally welcome by all chipmunks. Mine also love shelled almonds and pine nuts. I've never tried mine on just milk, the bread is probably alright as lots of chipmunks like toast. Try to make sure she has access to fresh water, either from a bottle or a bowl.
Her behaviour sounds OK, not all chipmunks race around all day, and she is just getting used to a new home. Actually when you say she is sneezing is a good sign. I've never seen it described in books, but all my chipmunks will make a sneezing sound, it's quite faint, and you think they have got some dust up their nose when you first hear it. It's not that all all, they only make the sneezing sound when they are really happy or pleased about something. It's a short repetitive sneeze they make for a few seconds then normally stop. It would be a different case if there was a discharge from the nose (mine have never caught a cold) and she did it all the time, but I think you have stuck lucky and she is very happy with the home you have given her.
