I'm going to toss my little experience out here. I have a 10 pullets of various breeds, all March chicks. I was watching for squatting and listening for egg song. Didn't even have the next boxes ready since I seen no signs at all. They have a large steep bank next to the garage fenced in that they have access to all day. One day I walked past the pen after fixing a section of horse fence and noticed a pile of funny looking rocks, as the weeds are dying back. It was a clutch of 63 eggs. Not knowing the age, we were going to cook them up and feed them back. But after cracking two and getting a smell, they were all tossed. I immediately put a large litter box with a deep layer of shavings in the coop. I marked 3 of the eggs from the top of the pile and put in the box. After removing the rest of the eggs, I made sure the nest area was destroyed and any weeds near it pulled out or knocked down, to discourage laying in that area again. Mine were good girls and took to laying in the box right away without having to lock them in the coop. I still do a very close inspection of the pen now at least once a week for any new hiding spots. Two NH lay first thing in the morning, the one GLW in late morning and the one EE (white/black exactly like Toxic Chicks') has started just laying this week in the afternoon. And to this day, I don't see any signs of squatting (other than when the rooster jumps on them, not always by choice) and have never heard an egg song from them. Think the Australorp has just started laying, the 2 Orp girls and other EE should be starting soon. 2 Anconas will be a little longer, as they are the youngest by a week or two.