Fully feathered and with those temps, you don't need it.
The purpose of locking them in for a few days is to teach them that this is their new home. Up to you if you want to do it, but IMO it's easier and less stressful than chasing them down for the first few nights to get them to go inside.
The purpose of locking them in for a few days is to teach them that this is their new home. Up to you if you want to do it, but IMO it's easier and less stressful than chasing them down for the first few nights to get them to go inside.