I get it, Yeah I saw those, nice pics as well.
Two points others wrote that I'd have to agree with:
1) You should be careful about ingesting substrate. While it could be harmless and pass with no problems. Duh, in the wild they don't have a clean tub to eat from. IMO it's better to not ingest any substrate to start with.
2) live is a no no as well, again in the wild they have to catch and esat live prey, in captivity however, they can be trained to eat previously killed food. even if all you do is stun the prey, you've reduced the capability of the feeder item to fight back. I have a snake (Savannah) with scars from feeder animals. I've also seen pics and read stories of snakes seriously injured by the feeder animal. While it is rare, the snake does sometimes lose the fight.
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Thanks,
Dave Colling

www.rainbows-r-us-reptiles.com
0.1 Wife (WC)
0.2 kids (CBB, a big part of our selective breeding program)
LOL, to many snakes to list, last count:
13.24 BRB
12.14 BCI
And those are only the breeders 
lots.lots.lots feeder mice and rats 