Our previous Corgi was fed half a cup, twice a day, and was average sized at 30 lbs.  Our new Corgi Bogart, since he is still growing, gets 2/3 of a cup, twice a day.  Also we give him fresh veggies in the middle of the day, a couple of pieces of carrot, green beans and apple.  He is also VERY active, with a 30 minute walk every morning, and lots of play fetch in the back yard, plus a shorter walk at night.  On weekends we run a mile each morning, and go to the dog park to play with other dogs and run around.  Tomorrow, we are going sheep herding.