I'm not convinced there's a pattern to the fights, despite everyone listing stuff above. I went to the Kennedy docks and did 14 maximum bet matches in a row, recording each result to compare it to the strategies above.
Supersulan's "bet on specific fighter names" strategy: 5 wins, 4 loss, 5 matches where neither chicken had any of the names he mentioned
GORBASH CELT's breed rock-paper-scissors strategy: 1 win, 13 losses
Always bet on Black: 7 wins, 7 losses
Always bet on the Underdog (listed in the UKGamingBureau video above): 4 matches where they had the same wins, 5 wins, 5 losses
So basically we have three strategies that seem to be basically random chance, and the breed strategy failed bigtime. Since some people have reported success with the breed strategy, I don't think the strategy is exactly wrong--I just think the whole thing is random chance.