If organic matters to you, there are organic feeds. They definitely are more expensive. Also some non-GMO feeds are out there.
I'm glad you posted that 95% of what she eats is her feed. Treats should be, well, just treats.
One thing about mealworms... they contain a lot of fat. So do black...
Everything that is NOT her regular chicken feed should be considered a snack. The feed is designed to meet all nutritional needs, and nothing else is necessary.
Which is not to say, don't give her snacks. But they should comprise no more than 10% of what she eats in a day.
My chickens'...
I would suggest an All Flock or Flock Raiser feed. It has higher protein, to compensate for the "snacks" you're feeding. You will need to supply additional calcium on the side, like a small dish of oyster shells.