I have recently had experiences with frozen eggs.
I realized that I needed to collect in the afternoon instead of the morning time due to my hens laying schedule. I had less frozen/cracked eggs and generally the eggs I retrieved were still faintly warm.
Not sure if it helped, but I utilize
wood shavings for my laying boxes. I got some finer material in there instead of flake and it seems to have helped insulate out some of the cold. The girls kick a good bunch of it against the back and sides of the laying box so they a hunkered down in it.