I know it sounds crazy, but as a Florida native I understand why. I cannot tell you the large amount of invasive species that have flourished and otherwise been exceedingly detrimental to the native residents. It seems due to the climate, most everything thrives whether it's meant to be there or not. It is unfortunate that responsible owners get put into the mix, but how many people do you know get ducklings on a whim and decide later to just "release them" because they're more work than the people bargained for? It's been the same with the various reptiles and fish that have wreaked havoc on native wildlife. The only reason I can think of them allowing Pekins is because they are so large they are not at risk to fly away and integrate with wild populations.