Do you switch feed when they are molting? Do you have oyster shell always available? What are the signs of your calcium problem? I have finally settled on an 18% protein mixed flock feed with oyster shell always available. Have used Dumor, Naturewise, Purina layer, Producer's Pride before with no issues. Cost depends on where you buy feed, sales, etc.. The prices sure have gone up since supply chain issues happened. Flock dynamics change so I buy feed accordingly. I also have males, so layer feed is not good for them. The girls will eat the oyster shell as needed, and I also give them all the crushed eggshells to recycle.My Layena just changed color, from a sort of milky tan to a brighter yellow, I buy at the local feed store. Hens are taking it ok. I wasn't aware of Dumor brand, which does say purina on it, until my helper gave me a bag of hay for my bunny in a dumor bag and I actually read the bag. Is it better than Layena? Cheaper? I've been feeding Layena since 2010 but have had intermittent calcium problems with my hens, it's not enough by itself especially coming out of molt