I must not have very vocal chickens because I have yet to hear the egg song and we have one layer who started Friday and has given us 3 eggs. Is your hen squatting at all? Our layer does squat so that's how I know it's her laying because the others don't do that yet. Anyway it shouldn't be long now I don't think!
When I opened the chicken coop door to see if their where any eggs August ran in and randomly sang the egg song for me.....I don't know if she was squatting or not.