suger isnt really good for them .. but the small amount thats in pizza or cheese type crackers doesnt hurt them at all .. chocolate is a no no.
Im not talking a huge slice but a about the last inch befor ya get to the crust type of slice once and a while .. its a treat for them. you can also give them a piece of what ever meat your eating also . they are mainly carnivores and protiens are very important in there diet . a small amount of milk is ok too, but only once and awhile ,,, but make it a very small amount . raw egg also . they do need some fiber though .and they get that from the dry cat food.
Ive owned 5 ferrets over the years and ive found that a catfood type diet seams to be alot better then a just ferret food type diet . i've tried offering bolth foods at the same time and they will ignore the ferret food most of the time .they know what they need and will only eat so much at a time. They can also survive for a week without food .. but ive never let mine go for more then a day without fulling his dish.
most of my Ferrets lived long lives 6-8 yrs (one escaped thru a dryer vent though and was lost )7 yrs is around avg for a domestic .
If you find that it uses a corner for a bathroom in the house, its a good idea to put a litter pan there for it. Ive had to do this for a few of mine .. but once there well litter trained they will ussually jump back in the cage to go .
also be shure they have toys to play with ,Balls with bells and squeaky things and always favorites ..