I just had a drop off (50%) in egg production, its spring and I have recently installed 16 nesting boxes of this design. My lay-age hens are nearing 2 years old (I didn't start incubating until recently -- I have a batch that should start laying this coming month). However, this drop-off was sudden (over the course of a week or two at most). I know where these hens "hide" their eggs and they aren't there. Even so I've looked thoroughly and not found any new hiding places. I've not changed their diet.