One thing I never did in the pro kitchen when roasting chicken was to dump the juices out of the cavity. I do it all the time at home though and it seems the chicken turns out better this way. Of course I'm only doing one chicken at home whereas in the hotel kitchen I'd be doing a whole case of chickens. They never turned out with crispy skin when I did them in large amounts.
I wonder if the juices keep the temp a little lower.