Yes, I buy them buy the bag, which is forty pounds. They are always solid and heavy, but I find that helps keep my piggies litter box with them in place (they use fleece with just a box now of pellets). One bag would totally fill a 2x4 C&C cage twice when I used pellets as bedding.
My pigs don't eat them, and my pigs LOVE to eat everything (wood shavings, carefresh, any paper or cardboard...), but all pigs are different.