To get this Achievement you must shoot 7 chickens under 10 seconds on the level The Hornet’s Nest.
A bunch of chickens can be found in the market section of the level, but secure it first so the enemies don’t accidentally shoot the chickens.
A grenade launcher helps a lot with this Achievement.
⬇️ Timestamps ⬇️
0:00 Where The Market Starts
0:47 Chickens In Market
1:10 Achievement Unlocked