Have a little faith ;)They wont try and escape. they will just explore the area around their coop.
When people come to buy birds from me they are always amazed at the fact that my hens dont leave the premises despite being able to. But why would they? They have food, water, treats, shelter, dust baths, places to range and perch and a safe place to roost and lay eggs. I leave my birds out alone all day when I go to work and they stay on my land. When I pull up in the car they come running from all four corners to see what I've got for them and in time yours will be just as friendly and tame.
By letting them out about 5pm on the first evening, shaking the corn tin and sprinkling a few tasty treats as you wander round with them you will be like the piedpiper. You will have their attention and they will soon learn that you = treats so they wont run away from you.
I have 3 coops on the go at the moment but let all my birds free range together and wander in and out of each others pens to eat each others feed which can lead to a bit of coop hopping come bed time. I let them all out this morning but needed to get them all back into the right coops quickly before dashing off to work at lunch time. Armed only with a fork and a bowl containg corn, cheese and a bit of tuna in olive oil, I got 5 adult hens and a cockerel into their coop first by calling them over to me and shaking some of the treats into the run. Then the two young males who have only lived here since sunday evening and dont know their names yet but responed to tapping the fork on the bowl at chicken height, were inticed into a different coop using the same method. Followed by a broody who comes to her name and her 4 three week old chicks who were ushered into their broody coop.
Chasing chickens is frustrating and time consuming. So like people..., its allways better to motivte them towards what you want with rewards than to drive them towards it with fear.
Dont be affraid to let them out, they will love it and you will enjoy watching them have their freedom
Let us know how you get on.
Buffy