How old are they? Is your yard fenced? Do you have predator type pets too?
We have a very high fenced yard and the way that worked best for me was to let them out for just a little while before dusk. They weren't very old, maybe 6 weeks. We locked them in the chicken house for 3 days so they would know it was home. Then when they went out just before dusk the first few times it left them with not much time to get distracted playing. It took a little herding but they did go back in the chicken house. Each day we let them out a little earlier till we knew they would go back in for sure. After that they got to be out all day. Happy chickens!
After the chickens have been in the coop and run for a few days you can start allowing the chickens out for a short time. It's good to let them out in the evening at first, because then they will come back at sunset.
You can then extend the time. Then you will be able to allow them to stay out all day when you are home on weekends, or whenever.