Mechanical Chicken is a reward for completing the quest An OOX Of Your Own. This little bugger is not BOP and since it is a quest reward it is rarely sold on the Auction House and fetches a lot of gold.
How to Start?
In order to get this quest, you must have completed all the OOX escort quests in Tanaris, Hinterlands, and Feralas.
Find OOX-17/TN! - http://www.wowhead.com/?quest=351
Find OOX-09/HL! - http://www.wowhead.com/?quest=485
Find OOX-22/FE! - http://www.wowhead.com/?quest=2766
Quests are started by these random zone drops.
Tanaris: Ambush is 3 scorpions.
Feralas: Ambush is 3 yeti.
Hinterlands: Ambush is 3 wildkin.
Warning: These quests reward Goblin Rep and Cost Bloodsail Rep.
Anyone know if these drops are still in Cataclysm? Might be worth stocking up on a few of these incase they are no longer attainable in Cataclysm. They sell for 1-2.5k now, just think of the price they could fetch if no longer available.