Ok, first things first, do you have an auto turner, if so, no need to mark the eggs, just put the "little" end down, the rounded end up, second the slowdown on the egg laying is due to a food change. That's normal. I recommend no layer at all.  Hear me out. I feed all my quail starter mixed with wild game growth and plummage, the reason is you get about 38% protein this way. It's the absolute highest protein gain you can get for quail without doing your own "scratch" type feed. I get 18-24 eggs a day with this feed. It has always been my go to feed for,quail as it was taught to me by my uncle who has a huge farm in Texas with over 20,000 quail and all kinds of other birds. Try this feed combo, wait a week and see if there is a big influx in eggs. The first time you do it it is expensive buying both bags. It costs 19.95 for the plummage and growth and 14.95 for NON MEDICATED starter. Then I just buy a bag a week, and alternate the two so I always have the feed. I have a lot,of,birds however so I need a lot of feed. I see here not to many have the quantities I have so you might not need a bag a week. It all depends on how much your quail consume. Pm me if you have any further questions. Hope,I helped