It varies. Depends on the time of year and how hot/cold it is for the eggs in shipping, how kind the postal workers are and how well they are packaged. I've had some really well packed shipments still wind up with 0 hatch. And some that appeared packaged bare minimum that arrived miraculously fine and have had a good hatch. I think the general rule of thumb is 30-50% and to hope for the best. But I also have needed to buy several batches and keep on hatching to get enough to start up in a breed I want and can't buy them as chicks. Alot also depends on how well you work your incubator, temp & humidity. Key word here is patience, and also don't spend more than you don't mind losing if your eggs get smashed or don't hatch.