how long to keep chickens in new coop?

my husband and i bought chicks. they outgrew the grow box space faster than we thought and we moved them into the coop since they were escaping. he thinks they only need to be in there 3ish days and they will imprint to their new home. i thought it was at least a week? i'd hate to have them run away once we let them out....

is there a good timeline for keeping them in? they are not full grown yet, but bigger than a football at least (not including the head, legs).
thanks!

I'd suggest you let them out in the afternoon/evenings after a few days. They'll want to return to the coop before it gets too dark. If any do not return, they've only had a few hours to wander off and shouldn't be too hard to find. Check under stuff, behind garbage cans and boxes, they'll be hiding.

Increase yard time as you see fit.

As far as a timeline.... Are they fully feathered? If so they're good to go. They'll just have to watch out for/learn about predators.