What is there actual age? You mention a year of eating your yard lol, are they a year? Like Parront said, lots can contribute to egg laying numbers! Have any of those other factors changed at the same time as their option to free range?
If they have always free-ranged since POL and you stopped that abruptly one day, it certainly can affect laying. But yup sod can be pricey. That's why I couldn't believe my friend's friend does that regularly! But for me it is free lol. Though she does not buy a roll, just a length of 6-8'. Heck maybe she trades eggs lol.
I have never sprouted grain...maybe I should try! Is that easy? Would be a great addition to winter feeding here in Michigan! Looks like a new thread to start!