They mostly do it when their tired. Older ferrets do it more, mine do it when their hot a lot, and like to lay down on the cool floor or tile.
If Pooka is doing it, it could definitely be linked to the kibble (depending on what kibble you have). Ferrets get most of their energy from fats, and kibble uses carbs for energy. This causes the ferret to have sugar spikes and drops. Raw, on the other hand, keeps the blood glucose at a more steady level.
That's also how they take a break They are running, jumping, playing, flat ferret, get up and carry on. It's like us taking a sit down break from work, except they only need 30 seconds or so.
Ferrets: Contessa Kitties: Watson, Oskar DIP Sinnead, Vincent, Boris, Zeus and Athena, Willow, Mr. Frodo, Indie, Lucrezia, Judge, Odin, Miss Emily, Suki, Cody, Aristotle, Butterscotch, Frankenfurter. RIP Herne, Ligeia, and Mr. Stubbs