Freshness is one thing and then the hens diet is another main contributor. Our hens are now firing on all cylinders so we're at full capacity although that's not much as they're all getting on a bit now. The difference between a free range home egg vs a typical supermarket egg is significant and probably one of the greatest differences you can find in the food world, supermarket eggs are a shadow of their free range cousin although a lot cheaper and easy to find.
Most of ours are consumed the day they are laid, often within a few hours. The yolks sit very proud in the frying pan and are hard to pop, the colour is almost orange and the white has a distinctive bloom to it.
I would certainly look out for someone selling eggs at the roadside, we used to sell about 1.5dzn a day when we were in the UK just with an honesty box (we had around 30 hens then)