Here's an answer
The fights last 15 minutes. Most times than not I've seen the judge with a stopwatch (sometimes two, more on that later) to do the official timing. The clock on the wall might be used for timing the bets prior to the fight, since according to the rules the judge may only give up to 2 minutes before the fight starts to place bets.
Here are the rules I know:
1) The judge may cancel the fight and call it no contest if any of the following conditions occur:
- a rooster seems scared or refuses to fight when tested prior to the fight start
- a rooster flees during the first minute of the fight
- a rooster looses both spurs during the first minute of the fight
2) A bird will loose the fight if any of the following occur:
- the rooster dies
- the rooster flees and refuses to fight
- the rooster is not standing on its two legs for more than a minute
If a rooster flees, the judge will grab both birds and set them back down at the center of the pit. He will repeat this until the bird runs away for the third time, and at that time he will stop the fight. For the minute count, I've usually seen the judge use a second stopwatch and not use the wall clock.
3) A fight will be called a draw if any of the following occur:
- both roosters are not standing on their two legs or stop fighting for over a minute (usually happens when both birds are blinded)
- the fight goes on for 15 minutes without a winner
Hope this helps!
Carlos