If a lucky egg is used, then the XP can be doubled for 30 minutes, and some players use that to evolve Pokemon during that time to double their XP increase.
But the animations takes time... and it can take 25 to 30 seconds per Pokemon to evolve, so 30 minutes will mean roughly 60 evolutions.
Is there a way to make it faster? Otherwise 2 lucky eggs will need to be used if more than 60 evolution is needed. (and also will need to look at how Pidgey evolve for 40, 50 times).