This plugin allows you to breed animals with only a single parent. This plugin uses processes from vanilla Minecraft and will thus be compatible with other plugins and advancements.

Coded for 1.18 using reflection and might not work for other versions. If you do give it a try anyway, do let me know if there are any issues (or if it is working as intended!)
This resource is part of my custom series. You can view the full list here, prefixed by [Custom]. This series comprises of custom requests from server owners, where I help them out for free and in exchange, I keep all rights to the resource. I am releasing them here for any other server owners who can find a use for them.