Some people hang a head of lettuce in the coop for them to pick at, in the winter I put hay or leaves in the coop and spread scratch grains in it, this keeps them occupied for a long time scratching for snacks.
The single most popular source of chicken entertainment in my flock is a scratch block. It is easily found in most feed stores, is inexpensive and lasts for months. Chickens never get bored with it, and they spend hours pecking away at it, slowly liberating the seeds in it. It's also one of the best insurances against feather picking.
Girls are playing king of the castle on my truck and helping the wife in the garden!
Made my own flock block for them and they love it. Hang one in the coop every couple of days about hour or so before the light goes out at night. Starting to get cold now, about -17C last nite. Interesting to see if we have enuf ventilation for them. Am using a heated pet bowl for the water.