I was thinking the same thing about re chipping them. I'm not sure. I paid $15.98 for these 8 quart bags from Homedepot. I'm pretty sure I'm going to buy wood from Homedepot next time and chip it. I will be sure to document my experiment and post it here. I have a logging company in my area and am thinking of buying a $1000 load of Douglas Fir Tress, if I can. That is if they'll seperate the trees up.I wonder if it will go through the chipper/shredder? I had a BIG bag of cypress mulch a couple years ago and the pieces were WAY too big for even a large tortoise. But it also had a bunch of stuff that looked like moss mixed in. I tried to run it through the shredder to get it smaller, and it just went right through, not changing sizes at all. I don't know how much you need, but Chewy.com sells Repti Bark (fir) in largish (8 Quart) bags for $15.98, and it's smallish pieces. I generally buy a bag each time I order something from Chewy so I now have a nice backlog of substrate for when it's needed.
As far as how much do I need ... I want to cover my pens with this substrate. As you all know I live in the desert so to have a more natural substrate for some of the torts. I need to cover the sand with something. A light covering of this wood or bark would be better for them I feel. Humidty and less sand to cause impaction. So as for how much do I need ... About a dumptruck load would be sufficient.