Average feed per hen should be roundabout 1/4 pound per day. I would weigh out that amount (2.25 pounds) and give it to them and check back throughout the day to see if they've polished it off early or not. Personally, I don't leave feed out 24/7, I feed in the morning and will top it up a bit after work if they've cleaned it all up. I know that on a typical day, my layer coop will eat a little under a scoop and a half of my feed, so that's what they get. If they start leaving some at the end of the day, I back off. Fewer rodent issues if there isn't feed sitting out overnight.