Marking quail eggs

When I hatch chicks and ducklings I write the date they are set and the expected hatch date on the top (air space) of each egg with pencil. Due to the color blotches on the quail eggs and the fact that they are so tiny I have recorded the expected hatch dates in a memo document on my smart phone where I keep track of all my hatches but not on the eggs themselves. I kept open spaces between hatches but I think I might have messed up my spacing when I candled for clear eggs so in the future I want to figure out a way to write the due date on the eggs. I stagger hatches so I have a separate incubator that I use as a hatcher and I need to know when eggs are due so I can move them two days before. Sometimes when hatches are back to back I have let them pip in the incubator and then move them to the hatcher but the quail hatch so fast that my first test hatch actually hatched in the incubator.

I guess I could just mark the beginning and end of each clutch with a piece of cardboard or something in the incubator but I do like having it on each egg in the hatching incubator so if I have back to back hatches I know if they are late or expired, especially since I can't see anything when candling the quail eggs except dark (developing) or light (clear).

I thought perhaps a silver Sharpie might show up on the dark spots but I have not used Sharpie on hatching eggs before, just pencil. Crayon won't work well on the shell and the quail eggs are so small that they only have room for the day without the month, although it should be obvious since they are lined up in order. I wonder if fingernail polish might work except that they need to be able to break through the shell so I would not want to make it too hard to hatch. Perhaps color coding with colored pencils would work as long as I record the color with the hatch date in my hatch list.

How do the rest of you mark your eggs to keep track of their age in the incubator with staggered hatches? My incubator holds 120 quail eggs and I have been setting quail eggs once or twice a week. I have a break now since the wildlife rescue moved the quail outside and they are either not laying due to stress or something is getting their eggs. I am planning to buy 4+ dozen eggs from someone as soon as he collects enough but he may not be getting ten a day as he originally claimed. My Texas A&M quail are just a week old so I have to wait for them so start laying in order to hatch my own.

 

I was thinking silver Sharpie would show up well but I could get different colors and just dot them since I keep the hatch date in my memo. I like to have the dates on the eggs when I candle so I can see that they are developing. I guess I could put the date to transfer them to the hatching incubator instead of the hatch date but I generally just subtract two days from the hatch date and that is when they go in the hatching incubator.

I like to schedule hatches every 4 days so I can get one group started before the next hatch but right now I have hatches back to back as I have been setting smaller numbers at a time and setting them more frequently. The challenge I will have is hatching quail with ducklings and chicks but I should be able to separate them soon after hatching or use some sort of dividers to keep them separate during hatching. The hatches so far are test hatches to check incubator settings and fertility.