I have racks based on both. Each works better for different reasons. The smaller litter pans are good for breeding and mice. The larger mortar tubs are great for growing up rats to larger sizes.

Key in any rodent tub is smooth concave sides and corners. If there are any clear ridges they will eventually start chewing and get out.
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Thanks,

Dave Colling

www.rainbows-r-us-reptiles.com

0.1 Wife (WC and still very fiesty)
0.2 kids (CBB, a big part of our selective breeding program)

LOL, to many snakes to list, last count (05/26/2009):
36.51 BRB
29.42 BCI
And those are only the breeders

lots.lots.lots feeder mice and rats