I had two out of the 12 hatch. A little over half started developing but then crashed at various times. My eggs were placed under a broody hen. I don't like to rate a seller on hatch rate as there are just too many variables that affect the hatch that the seller has no control over. In this case I found that much of the problem stemmed from the loose air-cells. The chicks were devloping but the shifting air-cells makes proper functioning of the egg membranes extremely difficult. I realize that loose air-cells are a common problem with shipped eggs however the problem is exacerbated when the eggs are not fresh. When an egg is freshly laid the air cell is very small. Shipped that way, there is little room for it to become loose. The longer an egg sits, the larger the air cell becomes, and then the more potentially damaging a loose air cell is. In my case, I think my eggs sat for at least a week, in dry conditions, in order to have air-cells that large. The seller has many auctions going at one time and apparently cannot keep up with the demand resulting in slow shipping (9 days in my case). The complete lack of communication was why I left negative feedback. I also feel they are just trying to maximize the $ they can get from their flock and are shipping ageing eggs in order to do so. I would never buy from them again and will share my opinion with anyone that asks me about them. It is not a good way to sell eggs long term.