I used to get a lot of die off at the beginning... now, not so much. I do find the pinhead crickets to be more tender, the larger size of small and the mediums tend to be more robust, shall we say?
One thing I did as the pp mentioned, is to clean out the dead ones as soon as you see them. Dead crickets can give off a gas that can take down the whole lot. The more dead crickets in the bin, the faster this process will happen. I'm not sure what's right, but somewhere on the forum it mentioned that it's not wise to feed beardie the dead ones (they died of something afterall). Also, I use flukers as well, but I also put in some real veggies and fruit--not a ton, just enough to have some more variety, and well, in our case, I feed the crickets what I WISH my beardie was eating! :roll: Usually, some mustard greens, a chunk of butternut squash, etc.
I get very little die off now. I'm not sure if it's the cricket size, or the changes I made. But thought I'd offer up the info, in case it's helpful to you. I know how frustrating that can be--I paid for those!!! :roll:
Best of luck!
Em