Lots of people have mini bators. They usually only fit a few. I see auctions on ebay for 4 eggs all the time. My guess is they are trying to cater to that market.
If I sell 12+, I provide 15 eggs.
If I sell 24+, I provide 30 eggs.
If I sell 6+, I provide 8 or 9 eggs.
So like others said, some of my breeds, I have 1 Roo and 3 or 4 Hens. I want to sell fresh eggs, so 8 or 9 is all I can provide. By selling as 6+, the consumer pays for 6 and gets a couple of extras. I guess we could sell 9 with no extras, but that does not sound as nice.
Yea, I can only fit 7 in my bator (more if I take out the auto turner and hand turn) so the 1/2 dozen sales are perfect for me. I knew I would want to get the larger bator (and truct me, I do) but I would totally get in trouble with one that could hold 2 dozen at a time! As patient as my hubby is, everyone has a breaking point!
Yep, often when people sell 6, it is actually "6+" meaning there's going to be anywhere from 8-12 eggs. And, the number is usually for people who have small incubators, or because the seller isn't getting enough eggs at the time to auction more. If they did, half the eggs or less wouldn't be as fresh and be at the risk of fertility.