Any thoughts as to why production dropped?
On common reason for a production drop is the molt. With those temperature changes it sounds like you are north of the equator so it is not the seasonal molt. But there are several things that could cause a partial or full molt out of season. Are you seeing a lot of feathers flying around?
One common reason for an apparent drop in production is that some are hiding a nest from you. Since yours roam during the day this is a real possibility.
Is something eating the missing eggs? Many egg eaters will leave signs behind, eggshells or a wet spot. Some critters that do not leave evidence are snakes, canines, and humans. A snake typically eats several eggs and then disappears for two or three days to digest them before returning for more. If his is a daily drop it is probably not a snake. A fox or coyote would probably be more interested in the hens than the eggs so probably not them. A dog however will often leave the hens alone and enjoy eggs. Does a dog have access? If your hens roam, probably.
A human does not necessarily mean a stranger, often it is someone you know. Some family members have been known to do things like this as a practical joke.
There is always the possibility some of the girls are taking a break.
So what can you do? Put a mark on a couple of eggs and leave them down there. If they disappear something is getting the eggs.
Instead of letting them roam keep them locked in the coop or coop/run. If some are pacing as if they want to go to lay an egg you have a clue. If your egg production goes up then they either can't get to a hidden nest or you locked out an egg eating predator.
I checked around the coop to see if a predator was getting in but found nothing amiss. Could a predator be grabbing eggs in the daylight while the coop door is open?
I've seen fox, coyote, dog, snake, raccoon, skunk, bobcat, mink, and possum out in the middle of the day. So, yes, one could be.
