can recommend the meal worms as well-the roasted non wriggly variety,though they do like live worms to.
they can be gotten cheaper online but we used to get a big pot of them from a local garden centre for our girls and and even when they werent free ranging they saw and heard the pot coming from a mile off.
unfortunately henny,penny and ethel were older girls from an ex battery backround and were very set in their ways of not trusting or getting close to humans,but with a less complicated chicken; roasted meal worms are a common snack of choice, it must be an OCD thing as they get obsessive with hoovering up all the worm crumbs.
some people breed their own meal worms for this purpose,personaly woudnt do it as it involves roasting them for god knows how long in the oven,but for those that have no issues,it is a cheaper source.