There is a big difference in flavor and quality between brands. The generic house brands on sale can be awful. After getting a particularly bad house brand sale chicken I only buy Oregon grown Foster Farms. Eggs are similar but you usually never get bad ones, just not as flavorful.
And yes, it is dependant on the quality of feed.
Chinese raised chicken will help clean up China. They will feed them the toxic wastes we ship to them and send it back in a chicken. That way they can put the USA label on it. Semi/sarc
We get crappy eggs here in Tampa. Some brands are flavorless, other brands have blood in half the eggs.
We end up buying the more expensive ones, less waste.