Doesnt matter how big the cage is their still gonna shit in same corner! Ferrets need lots of space, they cant just live in a small
rabbit hutch because you cant be arsed to clean a big hutch. I personally clean everyday.
Also putting a kit on its own is not fair IMO. It would need to get out of the cage quite alot for run about.
Just saying, not having a go.
Mine live in shed and court, theres some pics on here somewhere if you search court or hutch in the search box.
As for food, kits want as much raw meat as they will eat, you can also leave dry ferret food down for them aswel