You need to dust there food with straeight calcium, of which you can get it at a petstore, like petsmart. without calcium, they can get brittle bone disease and be crippled. Without calcium, there bones will become jelloiy and they won't be able to walk right.

To dust there food with calcium, put there food into a tall baggie, put a pinch or two of calcium powder in the bag to cover them, then shake the bag and the crickets or mealworms will be covered with the dust, and then feed them to your geckos.