Here we can get Agway Layer, Purina Layena, and Nutrena Naturewise Layer. All say they're 16% protein. Are the "prebiotics and probiotics" in Nutrena viable/active? Anything in there help increase calcium uptake? Anyone have any experience to compare the Agway, Layena, & Nutrena feeds? We're tossing out some veggies now and again, too, but winter will not be as rich a time with fresh foods for them as in summer. The hens range in a large garden, but I can't imagine there's many bugs or worms left at this time. Thanks for sharing your experiences!