How long do alien eggs stay viable?

The ones on the ship were surrounded by a force field of sorts that preserved them. Otherwise they require the Hive's resin membrane to keep them alive. If you remember from the movie, the other eggs looked fossilized from not having the force field.

What fossilized eggs are you talking about? They were all under that layer of mist which seemed act as more of an alarm than anything although I guess you can’t rule out the possibility that it was also preserving them.

Regardless I’m sure they could survive outside of a hive or some force field. It’s difficult for me to imagine that the eggs of something as hardy as xenomorphs would just wither away in less than ideal conditions.

It has already been clear that xenomorph eggs only open when a life form gets near it. But if your talking about the amount of time tell the point were they start decaying, I can't answer that question.

The egg is a food source of some sorts to the facehugger keeping it alive. But once the nutrients inside the egg is gone the egg sprouts roots in to the ground to absorb nutrients near it kind of like a egg that is a plant.

^Can i see your source on that?

Concrete It was a long time ago but it came from a website called how does it work. I think but I typed in the google search engine do facehuggers have organs and that came up. So yeah but I don't rember