Do dragons lay eggs constantly like domestic chickens do? Because if yes, I bet they export the unhatched eggs to other nations. Spike actually has a Moses-like origin in that he was snuck into a shipment to Celestia's What's-It-Called School in the hope that he would be magically detected by customs and hatched. Worse idea: 99% of dragon eggs hatch, but most are exported as a form of local population control, and to disperse sleeper agents.