You said you were mixing 10-1, that is almost 10%. If it is actually less than that the effect will be lower. But mealworms are higher in protein and fat than most chicken feed, and also have a different ratio of things like calcium and Vitamin D3. So you are raising the protein, fat, and...
The feed you were using is already high in protein (you said it is 22%). By putting in almost 10% mealworms you are diluting a lot of their other nutrients.