Barnbum, looks like you are getting them the dead mealworms. If you get them live mealworms they really go crazy! It's a great source of protein for them.
I don't have chickens myself by my friend does. We are a mealworm farmer and we give their chickens mealworms all the time and they love the mealworms!! As they say, its like giving chickens crack!! haha!
BYW - if you are worried about keeping them alive don't worry. You can put them in the fridge. They slow down and you just have to take them out once every 4 days or so feed them a piece of carrot and once they are done back into the fridge! They can last this way a long time.