This is my primary loredump for all my changeling lore/headcanons. Some lore is not compatible with each other because of different changeling ‘flavors’, so pick and choose as freely as you like.
In many respects, changelings work very similar to bees. They have a Royal that lays a surplus of eggs, and drones that serve her any way they can. However, this is where a flavor split may occur depending on the story/roleplay…
Equestrian production makes changelings similar to ponies, in that drones can produce more drones without a Queen constantly laying eggs. Simple as that. This option is best for those who do not want to deal in alien bugmom shenanigans and just want a very simple and SFW changeling experience.
What I consider to be true changeling production is where a Queen lays all of the eggs for the hive, manipulates their genetics with alchemy, and takes on consorts from her drones to encourage certain genetics to be stronger in newer egg strains. Essentially the “genetic mastermind” route, where a Queen strives to improve her species at all times. Since changelings work similar to bees, incest is not a real concern, but this makes them very alien to other races such as ponies. Queens look VERY different from one another due to improving themselves with alchemy. This route is inspired by the “Of the Hive” series on FIMFiction. It can be considered mildly NSFW, and strange, so it is not recommended as a general Changeling experience. I recommend this path to people who want a wide variety of “truly alien" interactions while allowing for exploration.
What I consider to be a sort of ‘parasitic’ route. Changeling Royals make a common practice of converting ponies via alchemy/magic into Changeling drones (and with a bite, new Royals). Changelings can be hatched from eggs here as well, but are not a part of reproduction and are simply tools for their Royals. The Hive mind can be expanded easily by infecting ponies or converting them, meaning that a Changeling take-over is not at all impossible. I recommend this route for people who want to indulge in their power fantasies without much difficulty, and who want a straight-forward changeling experience.
No matter what path you choose, Changelings are expansionist by nature, so keep this in mind.
No matter what biology path you may choose (or if you choose to mix and match), most likely there will be multiple Royals in the worldspace. Meaning there must be a form of communication and treaty between them. In many of my roleplays (and stories I've read), there is a Summit of Queens. In this Summit there is a treaty of peace on common ground for as long as the Summit is held. These events are rife with politics and drama, and too much information being revealed can end with one or more dead Royals and fallen hives. It can take months or years to locate all Queens and arrange a Summit, but this is an optional requirement depending on your setting.
For most Changeling roleplays I include the concept of alchemy, a magic unique to changelings that can alter their genetics in a myriad of ways. It is a complex craft, and can result in abominations and sickly drones if one is not careful. Queens can use alchemy on themselves within their lifetime, rather than during rebirth, as a benefit of their royal blood, which is why many Queens look quite different from one another in most cases in the True Changeling path. Alchemy is not required, but is something fun I like to include in my roleplays and stories whenever possible.
Traditionally Royal Changelings are often forced from their hive upon their first laying, but hives with multiple Queens are not at all unheard of. Some of the biggest hives have multiple royals to oversee the hive mind, and even multiple hive locations.
Royals have 3 stages; Princess, Proto-Queen and Queen, as they age. A royal will be a Princess for 18-20 years before she has her first laying, upon which she begins the transitory process of becoming a Queen during the Proto-Queen stage.
Queens can live for thousands of years, if not indefinitely depending on various circumstances.