here recently i have had to keep my chickens cooped up in their run which is plenty big for them but its still not the same as free-range. but because of this the shells on the eggs are very brittle i can hardly crack the eggs for breakfeast without the shell disenegrating so i am considering oyster shell and/or grit. but i am wondering if i do this if the shell will become to thick for them to hatch out of when i do hatch eggs anyone know anything about this?