A world gives the player two volt goat herds to spawn with or a player already has a long-standing world with two volt goat herds.
If one or both of the herds are low in population and both goat herds are close together, the herds will merge together. The total volt goat population in the world goes from two herds to one herd.
May be in relation to Game Update 280490, specifically this: "Fixed bug preventing herds from merging together properly."
This update was targeted towards fixing beefalo overpopulation, but changes were made in herd.lua, which affects other mobs as well (in this case, volt goats).
This is a visual example of what I mean in-case the above was not clear.
Edit: As far as I'm aware, this affects the console versions as well.
Edit2: If c_countprefabs is not printing the amount of goat herds in a world, its because caves are on. To use c_countprefabs in a cave-enabled world, use
This will make the player say how many herds there are in a world.
1) Use c_countprefabs("lightninggoatherd") to see that there are two goat herds. [or ThePlayer.components.talker:Say(tostring(c_countprefabs("lightninggoatherd"))) if its a cave-enabled world] 2)Get one or both goat herds to be low in population (they are normally low when the world starts, but you can do that manually in long-standing worlds). 3)Get either goat herd close to the other one. See with c_countprefabs("lightninggoatherd") that goat herd population went from two herds to one. This is a visual example, viewed here. https://youtu.be/Oq9c9SA2lEg?t=120