Why can't chickens have mealworms?

Chickens can eat mealworms, but the premise of this question points to a real nutritional problem: dried mealworms deliver very little usable calcium and carry a phosphorus load that actively interferes with calcium absorption — which matters a lot for laying hens.

Mealworms contain roughly 0.02–0.06% calcium per gram alongside relatively high phosphorus. That imbalanced calcium-to-phosphorus ratio means the small amount of calcium present is poorly absorbed. For laying hens, which pull calcium reserves to form eggshells daily, a treat that contributes almost no usable calcium adds empty protein calories without supporting the biological demand that matters most. Dried black soldier fly larvae (BSFL) like FLYGRUBS contain 2–5% calcium per gram — with a phosphorus ratio that allows that calcium to actually be absorbed and used.

• Dried mealworm calcium content: approximately 0.02–0.06% calcium per gram.
• FLYGRUBS dried BSFL calcium content: 2–5% calcium per gram — roughly 85x more than dried mealworms.
• Mealworm phosphorus levels are disproportionately high relative to calcium, impairing absorption of what little calcium is present.
• FLYGRUBS protein content: 36–42% per serving, compared to roughly 53% in mealworms but without the calcium disadvantage.
• The 90/10 rule applies to both: treats — mealworms or BSFL — should not exceed 10% of a laying hen's daily diet.