system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the difference between brown and white eggs?

At my home grocery store, the only difference is that the brown eggs tend to be runnier with smaller yolks when compared to white ones, even though they are both grade A. Is this common, or is there really no difference?
gpt
The color of the shell. There's really no difference otherwise. 

I'd be willing to wager the difference in yolks you're seeing is coincidental. Fresh eggs tend to have tighter yolks, and they loosen up as they sit.