I would say the success rate is nice. Maybe 1 shipment out of 15 to 20 would have any broken eggs. Sometimes I don't feel like it would matter how you package. I have double boxed with layers of bubble wrap and the box on the inside would be ripped open. How could you possible prevent damage from that!!! As far as hatch rate I think It matters more who you ship too. Some hatch 95% and some hatch none. Some have nice incubators and know what there doing and some do not.How is your success rate for eggs arriving intact as well as hatch rate?