For an old ferret, the sleeping area is not furniture, it is the day: he will spend most of his hours there, burrowed deep and warm. Build it as a burrow he can enter without climbing — an enclosed sleep box at ground level, or a cage corner, stuffed with fleece blankets plus sleep sacks for burrowing — and site it away from draughts. Leave one blanket unwashed among the clean sets, carrying his familiar smell, so the nest keeps his scent, launder the rest frequently, and look each day for dry bedding and that he still stirs as usual when food appears and takes his wander; a ferret who stops leaving the nest is telling you something a vet should hear about promptly.
Warmth Without Overheating
Old ferrets seek warmth because sleep is when a small body cools, and burrowing is how a ferret regulates it: given depth of fleece, he will dig to the layer that suits him and surface when he is too warm. Give him that choice rather than a single heated spot — blankets he can get under and on top of, in a box that holds the warmth his own body makes. Keep the nest out of direct sun and away from radiators as well as draughts; a ferret who wakes overheated in a sealed, sunny corner is as uncomfortable as a cold one, and less able, at his age, to relocate himself quickly.
Hygiene for Deep Bedding
Deep bedding and an old animal mean laundry is part of care. Run two full sets of fleece in rotation: one in the nest, one clean and dry, swapped before the used set smells or feels damp to the back of your hand. The one unwashed blanket carried over is deliberate scent continuity — ferrets navigate by smell, and a wholly fresh nest can unsettle an old animal — but it is one blanket, not the whole pile, and it joins the wash once its replacement has picked up his scent. Shake bedding outdoors daily, because an old ferret sheds hair and dander into the pile he sleeps in, and a nest that is aired as well as washed stays inviting longer.
The Daily Rousing Check
Tie the nest check to something that already happens: morning feeding works, because it puts your eyes on him at the same hour daily. You are watching for a normal rouse — a stretch, interest in food, a wander — against his own recent pattern, and for changes that break it: leaving food he used to take, a nest wet underneath, weight you can feel has gone when you lift him, or sleep that no longer breaks for the usual evening activity. Note the date when anything shifts, in the same place each time; with an animal who spends his days hidden in fleece, the written note is often the only place a slow change is visible at all. His vet dates, weight notes and visit history sit in KinsLe's Pet Passport, whose packet keeps an old ferret's paperwork together between appointments.