Yes, they are definitely beatable, as it did happen on Einstein. Beating them twice, though, is very challenging. And if you were to custom-tailor an alliance just to beat those three, it probably wouldn't be able to stand up to other teams or perform as well in other matches.
The alliance I can see beating the SimChickenWranglers consists of 20, 330, and 2106.
The strategy is a total trackball defense one. I would have 20 grab an opponent ball right at the start of tele, incurring a 10 point penalty. 2106 would use its
chain driven manipulator to surround an opponent ball and grip it just enough that it is still herded, not possessed, and therefore not incurring any penalties. Then they must stay in the corner holding the ball the whole match.
Meanwhile, 20 would be lapping like crazy with their bot while playing keep-away with the trackball, to try and overcome the penalty points. I can see them getting 7-9 laps in tele, so that's 14-18 points.
Lastly, 330 would need to use its ability to herd while possessing to control both of its trackballs, and double hurdle every chance it can get. I don't see the other alliance trying to play the same trackball possession game, but if they do only the ThunderChickens can really hold onto the ball without possessing it. 148 and 217's defense could be problematic.
So, after all is said and done, I think that a real aggressive defense would probably be the best way to win. If they can keep up in Hybrid (20 can get 5 lines, 330 3, 2106 2 maybe, and the alliance might get a ball down), and be within ten points, then it's definitely a viable strategy.
In any other match, this alliance would be very strong with the dual-hurdling of 20 and 330 combined with my proposed trackball defense for 2106.