In my limited experience, different chickens have different habits. My Black Star takes a long time, sometimes as long as a couple hours but more often she'll go in for half an hour to an hour, come out for a few minutes and then go back in. The cycle usually repeats 2 or 3 times and doesn't always result in an egg. OTOH, if my white Leghorn is in there 5 minutes it's a long time and my ISA Brown drops an egg off the roost every morning before sunrise so she has no need for the box. My RIR can be anywhere from 10 to 40 minutes so she must be the "normal" one in my little flock.
