Wow, I never thought of using those plastic drawers...what a clever idea...I have 3 or 4 of them sitting around here. I might just have to mull that over
As we strolled through the building supply recycle store today I had a good hard look at shower pans and a couple of ideas popped into my head. The first was that they'd make a fine outdoor table for doing all kinds of stuff. Stick 'em up on some legs (DH is handyman extraordinaire) and use it for a potting table, or a table for mixing my grains for critter feed, or putting the scale on to weigh the bunnies...all sorts of stuff. Weather wouldn't bother it because it's fiberglas. The next thing that came to me was that it'd make an excellent rack for fodder trays! It's all slanted slightly toward the central drain hole, so you could set your trays in there with a large reservoir under the drain hole, rig up a small water fountain pump on a timer, and have it pull that water up and through some pvc into the trays where it would rinse and soak everything then drain back down into the reservoir. The shower bases were about the 3/4 size...about 4' by 3' and were priced at $40. The pump we found brand new for about $30 (bet we could find one way cheaper used somewhere), the store also had pieces of the pvc available. I'll bet it could all be put together for less that $80 or $90 and it would pretty much all be automatic. About all you'd need to do would be to get it set up and then refill your tray as you take the fodder out to feed the critters.
We only have 6 laying hens so the cost for grain for feed hasn't been bad, but we now have 3 rabbits and plan to breed for meat, so our feed costs will be rising. Time to stretch those grain dollars by sprouting 'em, I say

It won't be quite so necessary during the growing season because we'll grow lots of fresh stuff for them all to eat but it'll be super great over the winter when fresh greens are so scarce.
We had been thinking of making a PVC frame to hold the trays but we'd still need to figure some way for the water to trickle down without making a mess all over my hardwood floor. I'm thinking that with the shower pan idea, we wouldn't need to stack them...with 12 sq ft available all the trays could go on the same level which would free up wall space above the unit for shelves for storage.