The most I have seen in a box at once was 5 & I couldn't figure how that could be conducive to laying, but when I tried pulling a couple out, they went right back. Mine seem to round robin which is their favorite, but I have had as many as 12 eggs in one box in one day from 45 hens.
I have RIR's & get a couple 'ridged' eggs a week - some like yours, some more pronounced - all different sizes. I've used some, sold some at the market & never had a bad egg from them.
When I cull my flock, I separate a chicken at a time & give them a week to see their laying habits.
The brooder is solid @ 96 degrees. The incubator has been crazy-fluctuating temps the last 4 days. Mayve that is the issue? It flucuated at the beginning, then was perfect day 5 - 18. I hate thinking of the chicks suffering. Maybe I am just better off buying hens as I am not cut out for...
I have had a wierd hatch - first chick popped out, acted fine, I moved after 12 hours to breeder box (too soon?), then acted like it couldn't stand up, then died 8 hours later. 2 more hatched (I assisted one, didn't make it) the other was fine for 26 hours, then died. 2 more hatched, one is...