The treat hens would order for themselves
Yes, chickens can eat mealworms — the larvae of darkling beetles are close to what a free-ranging hen spends her day hunting, and the flock's response to a rustling mealworm tub is closer to a rugby scrum than a feeding. No other treat calls hens back to the coop as reliably, which makes mealworms as much a management tool as a food.
Protein where it earns its keep
Mealworms are protein-dense, and there are two seasons when that protein works harder than any other treat can. The first is the moult, when a hen is rebuilding her entire feather coat and protein is the raw material feathers are made from; a moulting bird looks scruffy precisely because her intake is being spent on regrowth. The second is peak lay, when protein supports the steady production of eggs. A small daily handful through the worst weeks of a moult is one of the kindest things on the treat list — fed with the ration, never instead of it, since mealworms alone lack the calcium a layer needs.
Dried or live: two different tools
Dried mealworms are the practical staple: shelf-stable, light, easy to store in a sealed tub, and simple to portion. Their one drawback is that they bring no moisture, so fresh water should always be near. Live mealworms cost more and need keeping, but they move, and movement turns a treat into a hunt that occupies a confined flock far longer — worth it for birds in a fixed run during a wet week. Either way, buy mealworms sold for birds or reptiles from a reputable source, and store dried stock cool and dry; a tub that smells musty or shows webbing from storage moths goes in the bin.
Fat is the brake pedal
For all their protein, mealworms are fatty too, and fat hens lay poorly and age badly. The working portion is restraint you can see: a small handful scattered per hen, not a scoop poured into a dish. Scattered is the operative word. Mealworms thrown wide over the run floor are scratched for, raced for and worked for; mealworms in a bowl are simply inhaled by the two hens at the top of the order while the rest watch.
Using mealworms to train the flock
Because hens value mealworms above almost everything, they are the ideal recall reward. Shake the tub, call the flock, scatter a handful — repeat for a week and you own a flock that comes at a rattle, which is worth a great deal the evening a hen is out, a predator has been seen, or the birds need shutting in early. Keep the reward small and the association strong, and never waste it by feeding mealworms pointlessly between training moments.
A treat this useful deserves to be deliberate, so during the moult, note the mealworm plan in KinsLe's Care Teams — the protein boost is recorded, the portions stay handful-sized, and every helper works to the same intention.