From my research its the two protiens that aid the hen in laying but that is online info so it may be a combination of both! The two are Lysine and Methionine. I'm glad it helped! The reason mine stopped was because we are off grid and didnt have our light situation figured out. I gave them light and that it still didnt help after about a month and thats when I discovered lentils. What breeds do you have? I have Australorps copper marans cuckoo marans and a mix as well as two turkeys!Seems like the lentils helped but I wonder if it's because they contain specific vitamins, vs protein. I gave my hens a 100-lb deer carcass two weeks ago and they picked it clean, all the while egg production dropping.