Production cut in half in a one week period. It could be different things, maybe a combination of different things. Do the eggs you are getting look like they are laid by the same hens each day?
1. Has there been a difference in lighting? Was there something creating extra light, maybe a security light and the bulb burned out? If their days got shorter they can stop laying. It's not just daylight but maybe artificial lighting.
2.
free ranging almost daily.
"Almost" daily does not mean daily. But, have they started hiding a nest from you somewhere. It can be someplace in the coop or run, does not have to be while out free ranging.
3. Has something started eating eggs? Maybe the warmer days have brought some critter out looking for food. Since yours free range (at least sometimes) a critter could go into the coop through the pop door and get eggs. It could be many different things but a dog would be high on my suspect list. Could it be a human?
4. Something stressful can sometimes stop some of them laying, at least for a while. That could be anything from a predator attack or scare, a change in the coop layout or location, a change in pecking order, running out of water for a while, a lot of different things that could change their normal day.
5. Sometimes they just take a break for no apparent reason.
Good luck in figuring this out. This kind of stuff can be really frustrating.