you could make something like this to go across the door(s)
https://www.amazon.co.uk/dp/B075FKPXQN?tag=duckduckgo-brave-uk-21&linkCode=osi&th=1&psc=1
It works for me. The chickens take a few days to get used to it and learn how to pass through, but it's easy to train them because you start by...