Overall excellent advice given in this thread.
One caveat I would offer to new keepers is that when specific amounts of feed are given, understand that applies to the number of chickens one has. One bag of feed will last 2 chickens too long before it may have had nutrients degraded. 4-10...
What you are doing now is probably the best course of action.
When a flock of same age/breed birds reach point of lay before summer solstice, one can be relatively assured they will all start laying in short order. But this time of year, some may take much longer.
It also wouldn't hurt to mix...