Hello all! We’re about to get our first hens. We’re going to convert a portion of the structure below into a hen house and screen it in for a protected run. I’m worried about the small-ish but not tiny rocks that are in there now. Should I remove them? I’ve tried to show a scale for the size w/ my hand in the 2nd photo. Are they too big for the chickens to mess w/ (try to eat) but too small for grit? Thanks for any thoughts…