I'm sorry about your losses, that's always hard. Genetics, ugh, nothing to do there, except for future additions, discuss egg size with the breeder, even ask to see the eggs if you can. For now, yes, subtract the scratch. Offer only their pellets, if they won't eat them, you can try mashing them into smaller pieces, like a crumble. If that helps, buy crumble in the future. You speak of adding "shell grit" to the food. First, those are two different things. Oyster shell is to add calcium carbonate to the diet, to aid in shell formation and contraction in laying. Grit is small hard stones, usually granite, that gets stored in the gizzard, to grind up seeds, etc. One is meant to dissolve, one not, they can't be both at the same time. Figure out what you have, and get the other, and offer both in separate containers, and not mixed with the food. The goal is to get the right amount of calcium into the hens, to aid egg laying. Layer food is calculated for the average, offering oyster shell is for those that feel they need more, so offered free choice. So the goal here is the right nutrition, to promote easier laying, and reduce body fat, which makes it harder. Next, how much exercise do your hens get? Good muscle tone is key to keeping the "innards" in the right places, and helps contractions in laying. How big is your run, do they get out of it ever? If they can't, for safety, can it be enlarged, and or different levels added, think multiple height perches, chairs, ladder, sawhorse, etc. Anything that gets them moving.. Digging for bugs, chasing butterflies, you get the drift. Instead of scratch, shred carrots, zucchini, cucumber, etc, and scatter SMALL amounts around the run, to hunt and digging for. Exercise and enrichment. Do this later in the day, so they've had to eat some of their pellets first. At worst, it's a better way to spoil your girls, and it might help.