Welcome to BYC! I know you've had plenty of responses already - so let me add mine as I've just gone through a similar experience:
Day 1: Chickens refused to leave the hen house.
Day 2: door opens - chickens refused to leave the hen house, we took them outside and put them into their run (they also have a fenced off area that sits outside their run for a bigger area) - they ate a little bit but mostly just sat around doing very little. At least they managed to find their own way in.
Day 3: Chickens left coop on their own - and ate but still chilled most of the day under the eglu cube (its a hen house on stilts) - I suspect this is because they feel safer there.
Over days 3-6: Especially on day 3 & 4 I noticed that when I sit in the garden tehy came out of the run and started exploring, but when I left they'd go back inside the run and under the coop. Days 5&6 they still showed that behaviour but less so and now they roam outside without me being there for about half the time.
And yes - I have a live camera to watch them when I am not near them...
We're on day 7 now and they are relatively relaxed and happy.
Now my hens came from what looked like a good farm where they were relatively relaxed and happy - at 18 weeks. So if yours were in less than ideal circumstances most of their adult life.. then maybe they will need longer to adjust. I would try sitting outside with them if its not too cold . that got my chicken to warm up to me.