I put eyes on every bird, every day. I don't/won't pick one up unless there is a sobering reason to do so. Scrutinizing is the right word. Observing or watching doesn't quite imply the critical eye that experienced flock keepers seem to develop. I spend a lot more time watching the younger pullets. It is my job to get to know them by behavior, shape, feathering, personality etc. This extra time spent with the pullets pays dividends when they become layers, later on. Have to establish their individual baseline for normal.
I sometimes like to rattle a can of pellets and have them trot a few steps toward the sound. This enables me to quickly see if anyone is less than spry.
If I am gone for a few days on a trip, I'll spend a bit of time catching up. Always nice to check them and see everything is OK.
I am always surprised how quickly these birds seem to grow if you haven't seen the young ones for a few days.
Walt