poly-fill pillow?

[k-bo.livejournal.com]

i'm making my dad a giant floor pillow, and i was planning on stuffing it with poly-fill. but then someone mentioned that poly-fill tends to bunch up, and if he'll be sitting on it i'm afraid it will definately bunch. are there any alternate materials i could use as stuffing? or something in conjunction with the poly that will keep it from bunching as much?