No that is breeding - I have produced high quality production Light Sussex, that have received best English at shows. Clearly what I am doing is producing high quality birds .
While there is not a genetic relation there is a inverse correlation between hen size and egg. Let's take the Leghorn a smaller breed with a weight of ~4.5 pounds but yet it lays one of the larger eggs. Now take a LF cornish - one of the largest breeds but lays an egg the size of bantam or a bit bigger.
I simply stated that the smaller birds will be your best egg layers I did not directly nor implicitly tell be to go breeding them. A good breeder can restore size as fast as size can be lost.
It can be if done correctly it's not something I do a lot unless I really need them to start laying.
If function followed form the poultry (and dairy, and beef) would be using pure breeding lines right now on the final generation. But beef and poultry have both switched to 4 way crosses. When assessing breeders the standard is the last thing I look at - and that is only occasionally. But yet I have one of the best strains of Light Sussex in the region.
Some people rely on standards while others rely intuition...