It could be the pullets laying and getting into their cycle. But with everything else you are giving them, you are diluting their feed so they don't fill up on the important stuff. I would quit all extras and feed them only their layer feed and oyster shell. Treats should not be more than 10% of their diet, even if they are healthy. Layer feed and oyster shell onlyYes, I make sure they always have it available to them. I also choose to give them veggies that are higher in calcium since shortly before they began laying. Idk how to give them more than I'm already giving them.
Could it be that 2 other pullets have begun laying and these are their first?