I free feed and have their food available. My hubby made a fabulous automatic feeder out of wood that another BYC designed and it holds over 50#'s of feed. I give treats of cracked corn, sunflower seeds and oats 1-2 times daily. I also feed veggies and fruit occasionally.
How about for a laying hen 4 pounds (4 Pounds = 1.8143694799999998 Kilograms) per 1-dozen eggs for a layer. The more frequently she lays an egg, the more feed she needs to produce the eggs for us. I got my numbers from Storey's Guide to Raising Chickens by Gail Damerow.
This is a good point that I didn't mention in my first post. Layers in general won't overeat when given layer pellets etc.
They will lay better for you if they don't run out of food...if free ranging some folks do throw food out a couple of times a day.
If they are penned in a run and cannot forage, it is good to make sure they never run out.
I have food down 24/7 for them....they also have access all day to my garden which is enclosed and covered its 12 x 45ft. And i give them snacks a couple times a day..usually oats or old cereal or cut up tomatoes.