Omg Robots

There are several ways how an egg can be created in the Digital World. Eggs can spawn naturally from scattered bits and pieces of data, sometimes just junk, and other times it might be remains of a Digimon - and occasionally when enough data accumulates, it can spark the birth of a new Digimon, and an egg is created. This is a common occurrence. Usually it will be one of the already existing species, but in rare cases it can be a new, never before seen Digimon.

The other is the end of a Digimon's life, usually when it happens naturally, like from "old age", or if it dies an unnatural death, but its data and Core remain untouched. The Digimon will shed all of the accumulated data down to its very core, and then the cycle will begin anew. The Digimon that will be reborn can be a totally different species, or the same one that "died", that depends on a variety of factors, but in pretty much all cases, the new Digimon will have no memory of its previous life. There are some exceptions, but those are very rare, and are usually special cases.

The third is when data is intentionally combined by someone to create a new Digiegg, but that is a pretty rare thing to happen.

The eggs can spawn almost anywhere in the world, and will remain in the spot where they showed up until they either hatch, or someone moves them. Depending on where the egg is, the shell's data might change to adapt to the surroundings, to help it blend in more for protection - like growing moss, corals, changing the appearance to a specific type of rock, changing color, texture, etc..

The surroundings can also sometimes influence what type of Digimon will be born - for example, if the egg ended up spawning somewhere in an ocean, it will most definitely become a marine Digimon.

The eggs usually hatch within months or years, but can stay dormant for decades or even hundreds of years.

Out in the wild, eggs don't have the best chances of surviving, as if found, they can be destroyed for "easy data" by other Digimon, or taken away by those who don't have the best intentions. A Baby I/II Digimon is also pretty weak, can get sick more quickly, and is an incredibly easy target, and so they need to either hide very well, or depend on others to survive.