Answer:
Because of the ferrets natural instinct for burrowing, soft bedding material is recommended that they can get underneath or cover themselves for sleeping. Bedding you can purchase for ferrets are sleep sacks and they particularly like hammocks
Bedding for ferrets - do not use wood chips, straw, etc. Ferrets like soft materials - you can use t-shirt type material, flannel type material - something that is easily laundered - it is suggested to launder bedding about twice a week to reduce ferret odors. Avoid bedding material with a loose weave - ferrets nails sometimes split when they get too long and tend to hang on loose threads (they need to be trimmed every 2- 3 weeks). I have read where ferrets nails have hung on threads with the owner unaware, and the ferret wrapped the thread around its leg cutting off circulation that resulted in amputation.
Ferrets love to sleep in anything soft and warm such as cat beds, old clothes, blankets, towels etc. Avoid typical small animal bedding such as wood chips.