It does sound a bit high, but to produce a pound of grain it takes about 150 gallons of water, and assuming about 1/2 pound of food eaten every 2 days it is about right.
As the previous poster said, a laying hen eats a couple of ounces a day, no where near a half a pound.
With a cursory google search, 1/4 pound of feed per day seems about typical, assuming 2 days per egg produced.
Maybe, a 'factory' hen that eats nothing but grain might do 1/4 pound of grain. But these hens will also produce very close to 1 egg a day, or about 9 eggs for every 10 days or so.