Are they making a mess because they're dying, or because they're shedding and sh@tting? I switched to a wood box probably 2 years ago; they can climb on the sides and space out more, and it helps keep them dry, which does wonders for keeping them healthy. You don't need a lid if you run 2" clear tape along the top edge of the box. They'll get to it, and if they jump, they just fall back in. Give them plenty of space to avoid congestion. Here's a pic of one of my cricket boxes... I actually made new ones recently, but this is the basic look I use and it works great. My boxes are 4' long, but you can do them on a smaller scale to house 1,000 crickets. Cleaning is a snap, just shake off the crates, and they all climb up the sides within 30 seconds. Scrape the crap to the center and scoop it out, takes maybe 2 minutes. Keep the egg crates off the bottom with 2x2's, so the crickets aren't living in close proximity to their droppings or any dead crickets.
You should try getting 2,000 crickets at a time and just work on keeping them alive for 2 or more weeks. They're cheaper that way.
