Answer to Question 1
When cracked onto a surface, a grade AA egg will stand up tall. The yolk is firm and the area covered by the white is small. A large proportion of thick white to thin white exists.
When cracked onto a surface, a grade A egg covers a relatively small area. The yolk is round and upstanding. The thick white is large in proportion to the thin white and stands fairly well around the yolk.
When cracked onto a surface, a grade B egg spreads out more. The yolk is flattened and there is about as much (or more) thin white as thick white.
Answer to Question 2
hatching egg production
hatching
growing
processing
marketing of the birds
They also often mill their own feed and render the offal and feathers to produce feed ingredients.