Liz there is no set rule on the quantity of food to feed.Each grey is different some will munch all day long others will eat morning,afternoon & evening.Try feeding mixed vegetables in the morning when greys are at their hungriest.I have 5 greys & my general rule is a handful/small cupful each,so if I'm doing rice ill do 5 small cupfuls.If you just fill a standard size bowl that is more than enough,as Makena said they will throw the majority on the floor & eat what they like It is a bit hit & miss until you discover what foods your grey loves