How much scratch and mealworms for how many birds? Grocery stores sell Oreos but they're not exactly good for us either...
Scratch and mealworms are both treats and should not be fed in excess of roughly 10% of their intake. My flock gets maybe 2-3 Tbsp of scratch a day total for 10 birds.
Mealworms have protein but they also have a lot of fat. You'd be better off switching to a feed with higher protein rather than trying to supplement via treats.
The scratch likely further dilutes down the protein they're getting, as a lot of scratches sit at maybe 9% protein?