Yesterday, Mojang rolled out the 1.11.1 update from snapshot 16W50A on PC with the latest features for Minecraft. This includes the fireworks propelled glider, Iron Nuggets from the furnace, the Sweeping Edge enchantment, and the new attack crosshair change.
However, the team didn't seem to get much sleep while a stubborn bug that caused crashes when zombie chickens were spawned. Thankfully, the restless night resulted in the 1.11.2 update to squash this and a few other issues. Mojang updated their former announcement with the notice, making sure people are aware of the potential issues if they don't update.
UPDATE: We've just released a small update - nothing too exciting - we've quashed some bugs and squashed a crash bug. Download 1.11.2 for EXTRA fun.
So it's safe now to have zombie chickens in your Minecraft game and server, just be sure to let your client update to the latest release.