It wasn't a complaint necessarily - they're just wondering why a breed advertised as something that lays brown was laying green eggs. That'd be weird to see when you're expecting something entirely different, like something is potentially wrong with the bird.
If you'd like to find who is laying what the easiest, put food dye on their booties and put colored zip ties to identify which hen had what color(s). Like if you make purple dye, put red + blue zip ties on one leg. Some people use lipstick (gross) or water-soluble, non-toxic paint on their...