I was looking at http://bulbapedia.bulbagarden.net/wiki/Egg_cycles, and I noticed that certain Pokemon like Nidoqueen, Moltres, etc. have base egg cycles, even though they cannot be hatched from an egg. Why is this? I thought that it might be for people who use Action Replay to get Legendary eggs, but I'm not sure? Or is it just the way Game Freak made it?
It is there to keep the game from messing up. If you make an egg with an Arceus in it, how would you hatch it with no egg cycles?? It would be there forever, taking up space in your game.
"...Please note that not all of these species can be legitimately hatched from an Egg,..." (Source: Bulbapedia/ Egg Cycles)
They must've hatched from eggs sometime in the past.