Okay, for sure our first layer is Jill the Delaware! I was lucky to be near an open window and hear "buk-buk-buk-Buh-CACK!" repeatedly from the back yard around 10:45, peeked out to see Jill appear in the coop pop-door sounding off, then go back inside where she continued her song. Everyone else was outside (they never go into the coop during the day, just to roost at dusk) and Jill's pal Pauline was on the perch over the coop ramp watching the pop-door's opening and clucking her encouragement/excitement. Jill was inside for another ~25 minutes before emerging to stand at the top of the ramp and shout her song over & over (so assuming that's when she actually laid). The others came milling around and clucking excitedly while she "sang". Well done, Miss Delaware!