While peacocks have beautiful trains, the splendor of those trains reflects the hard work of a farmer when raising the peacocks as babies.
Processed feeds are not just rich in proteins, they also contain fibers, carbohydrates, vitamins, minerals, etc. in recommended quantities.
Mealworms are a special source of food for your peacocks because they can also be used as treats to reward your peachicks during training.
You can give your peacocks some fruits, but not in large quantities. Fruits contain a lot of sugars and very few proteins.
If there are no peacock-specific feeds in stores around you, you should feed your peachicks with starter turkey or wild gamebird feed.