Do you have a roo? I also think that it is the time of year, seems like I go months not loosing anything and then....
I had a big white leghorn roo, just disappeared one day. Lost a little pullet 3 days ago, back into lock down! Ugh!
When I start loosing them, I lock them down for several days, then let them out for the an hour or two in late afternoon. Then maybe a day out.
Not perfect, but it does seem to work better not to have a set routine, especially of dawn to dark out of the coop routine, that really brings in the predators. I hate it too, I love to have them run, but I loose them too. ugh!