Waiting for my backyard chickens to lay their first egg

I read many posts on waiting what seems like forever for chickens to lay their first egg. I thought that would never happen to me, I would just walk out to the coop and, like magic their coop would some day contain 3 eggs. Well no such luck so far. I watch for signs: squatting, making some kind of strange chicken noises, combs to turn bright red. Nothing, their combs aren't even fully in yet. So I will wait for that glorious day when we have 4 chickens all laying eggs.

Dakota (in front) and Tallulah getting big. They are 5 months old. Which one will lay the first egg?