using a spawn egg to spawn villagers causes game to crash.

Were you wearing elytra at the time? If so were they enchanted?

Yes I was wearing an Elytra, no it was not enchanted.

Based upon the first comment I decided to do further testing to see if I could replicate the crash controlling other variables.

Completely removed Elytra Wings and put them in a chest, then used spawn egg: Crashed
Used dispenser to dispense egg: Succeeded
Used egg in creative and survival (No elytra): Crash.

Started Brand new world and used spawn egg: Succeeded.
spawn egg after generating End: Succeeded
Spawn egg after generating end city: Succeed
Spawn egg after getting new elytra and wearing it: Succeed
Spawn Egg after damaging new elytra: Succeed
Spawn egg after generating nether: Succeed
Spawn egg after enchanting Elytra: Crashed (couldn't tell if the crash happened before wearing elytra, as the item duplicated after enchanting it, I was wearing it automatically)
New world
Spawn egg after enchanting chestplate (Not Elytra): Succeed
Spawn egg after wearing new enchanted chestplate (Not Elytra): Crashed

the only thing I haven't done is attempted to use the spawn egg after trying to create another iron farm.

Thanks for testing this further. The reason I asked was that I reliably had these results:

• Start a new creative flat world with cheats enabled and no add ons

• Hold Elytra and use /enchant @p durability 3 and equip

• Spawn a villager using an egg and the game crashes (force closes)

Edit: It seems that using a spawn villager egg whilst wearing ANY enchanted armour will cause the crash. (On Windows 10 PC, couldn't reproduce on Android)

Glad I could help!