why are farmer villagers green and disabled?

[Arman]

when I found a village I found out that some villagers are green. I tried right clicking them to see what they trade but nothing happened. after an hour of experiments I found out that these villagers are actually farmers. I would like to know if this is just a glitch or just mandatory for the server.

Thank you,
Unteachable_

 

[Dakotaa]

These are "nitwit" villagers, and have no trading use. This is not a server feature, but part of the game.

http://minecraft.gamepedia.com/Villager

 

[Arman]

uhhh ok thanks Dakotaa