I hatch my own for meat as well as eggs, so to keep a certain amount of genetic diversity, I need to keep more hens than I can use the eggs. The excess eggs are taken to church. People that get them are expected to donate what they think is a fair amount to a specific fund. That fund has supported the Heifer Foundation, water for Haiti, or a program for the elderly here in Arkansas, among other things. Interestingly, the pastor contributes less per dozen than practically anyone else, but the idea is each according to his ability, not a set price. And no one else has to know how much anyone contributed for a dozen.
When I have the smaller pullet eggs, I put them in an 18-egg carton instead of a 12-egg carton once they reach a minimum size. And the people at church donate empty cartons. I have no trouble keeping plenty of cartons.