I have searched the internet for hours to find out how much an adult guinea needs to be fed. There is next to nothing there. I could only find one article about a Nigerian guinea project and the amount of feed was very low--too low to believe. During the winter there have not been very many bugs around for my birds to eat--so I assume I need to supplement all their feed. They don't ever seem interested in any kitchen scraps. I am just beginning my planting, so there is not much vegetation for them to eat. I am feeding an 18% protein chicken feed from tractor supply. So, how much feed (in cups) do you think I will need for my 18 birds?