Grade A. Jumbo eggs weigh a minimum of 30 oz per dozen. Egg sizes change with the season and the age of the hen, not necessarily just the type of chicken. You'll generally find more jumbo eggs in cooler weather and/or from older hens, although newly-laying young hens will sometimes release two yolks at once, resulting in a double-yolker!
It's surprisingly hard to find eggs done right! We rotate our hens to new pasture at least twice a week so they can hunt for nutritious fresh greens and insects. There are no dyes added to our feed, so the yolks are the "color of the season!"