You can usually tell what a group will do but you can't predict an individual. You are talking about an individual.
In general a flock will lay very well their first two laying seasons but after that second adult molt laying drops. It continues to drop after each successive adult molt. But that is a flock average. You will have some individuals that continue to lay well and you will have some that pretty much stop. Most will slow down.
A few weeks ago (6) she just stopped laying.
How do you know she stopped laying? Sometimes they do stop, sometimes you just think they stopped.
A common reason they stop laying is the molt. I know it is the wrong time of the year in Texas for the fall molt but sometimes they have a mini-molt out of season. Lots of different things might cause one of these molts. Are you seeing any feathers flying around?
A vey common reason is that she is now hiding a nest. Even if they are confined to a small coop and run they can be pretty good at hiding a nest even if they don't have a huge run or free range.
It's possible something is getting the egg but if hers is the only one missing it is not likely. This is an individual hen problem, not a flockwide problem.
At that age she is not likely to be laying that regularly. You can try locking her up for a few days and see if an egg does eventually appear. Or maybe do the vent check, six weeks since she laid should be long enough for this to work. If her vent is pink, soft, and moist she is probably still laying. If her vent is tight and dry, she is not laying. Maybe compare her vent to one that you know is laying.
Good luck with it. This kind of stuff can get frustrating.
