Hello guys..i have bought a bag of mash thinking i could give this to them as a Treat..I feed all 5 of my hens Layer Pellets in the morning and mixed corn as a treat later afternoon..i would like to try them on mash but looks powdery so any advice to with anything i can add to it and how much each hen will need...also should i add Oyster shell to them Mash....i awaite your Replys 

thank you