Pokemon-go – Are eggs predetermined before you hatch them

Eggs come in three distances: 2km (1.2mi), 5km (3.1mi), and 10km (6.2mi). The distribution of these seems to be relatively random, however 5km seems to be somewhat more common than the others. 10km seems to be somewhat rarer for now, however these numbers have become extremely balanced since the beta.

Pokemon's strength (and rarity) is usually determined by the distance you need to walk to hatch the Egg.

You can get any non-legendary (and egg-grouped Pokemon) from eggs, although some are rarer than others. For instance, you're much more likely to get a Rattata than a Growlithe from an egg.

Regardless of their contents, all eggs should be hatched if possible.

Unless I'm mistaken, the only way to remove an egg from your inventory is by hatching it. Since you have a limit of 9 eggs and eggs are essentially random, you'll eventually want to hatch all the eggs you can.

The questions then becomes "what order should I hatch them?"

I tend to hatch the longest walking length I can first, since the stronger Pokemon will help me out more in these earlier stages. But that's preference.

As for whether you should run around instead of catching Pokemon, that's a matter of balancing your resources.

If you have a ton of pokeballs, you'll likely want the candy and dust from catching Pokemon so you don't waste the resource. Or if you already have 9 eggs, you may want to rub and hatch a few so you have space for more.

Optimally you should never be sitting on excess eggs or pokeballs or potions etc, unless you have an excess of all of them. In which case, good job!