My hatching experience
I've read on Reddit, game FAQs, and here that egg are completely random. I've lead a very strict egg hatching routine since the beginning and it's quite the opposite.
I don't have stops around me, so I go and fill up, go home, hatch, repeat.
The first 300ish eggs were ALL from the same 6 stops within 20 ft from a lake. I mainly got krabby, horseas, etc. 1 lapras, 1 dratini. I quickly stopped getting new Pokemon.
I switched to the town square and on my FIRST batch of eggs I got my first Pikachu and chansey.350ish eggs later from square I have hatched first vulpix,magnetron, voltorb,porygon, 4-5 snorlax(first ever hatch), 2 dratini. The square is known to spawn snorlax regularly.
I'm sure you can hatch anything from an egg from anywhere, but it really seems the odds change by location.