Mine definately announce after they've laid...but, this sets the others off so you could be fooled and follow the wrong one! Hard to shut in until they've laid as some of my younger ones don't lay till after lunch so, you'd be reducing their day and thus the number of eggs you get!
Why not just fence off a smaller area so the eggs are easier to find?
Good luck! maybe an Easter "egg hunt" for real eggs this year!!
Judi