Eggs are sized for sale by weight, not size. Different aged chickens
produce eggs with different physical characteristics. The eggs in a
carton of a dozen will each weigh differently within certain
parameters... I've seen old ladies going through the egg cartons to
choose the heaviest and exchange them with ones from a different
carton... of course they could end up with more egg white and smaller
yolks. The amount of air space can differ by the type of chicken or
their time of month... egg shells vary by diet.
Commercial bakeries buy frozen eggs... buying eggs by volume, no
shells, is the fairest way... works for bakeries but not for diner
cooking. Eggs sold frozen in five gallon containers is what
commercial kitchens/bakeries buy. Commissarys, hospitals/prisons buy
eggs by how much yolk is in the container... cheating runs rampant in
the egg business, especially when dry eggs are in the equation...
could be more or less yolks/whites. The US military buys a lot of
eggs, especially frozen and dried... the US military serves the
highest ratio of yolks. One thing I know with certainty, the US
military does not skimp on feeding the troops. If you opened a 40
pound carton of frozen beef steaks you'd wish yould buy such high
quality steak. The US military gets the finast quality food on the
planet, unfortunately the US military has a goodly share of lousy
cooks. I never cheated the crew, some actually cried when I left. I
used to have big fights with the supply officer over the food bills.
The Captain would very often come through the enlisted men's chow line
for meals, I won every argument with the supply officer. The ship's
officers had their own galley, they voted on how much to spend, and
they were billed for their food, the officers were all cheapo
bastards.