The crimes of murder and homicide are defined under Philippine law in Art. 248 and Art. 249 of the Penal code, both of which reduce the act to the case where "Any person who, not falling within the provisions of Article 246 shall kill another". Murder is distinguished by having certain attending circumstances, such as "with treachery; for money; by drowning; with evident premediation", none of which are applicable here. In the case of homicide, it is necessary that the accused killed the person without any justifying circumstance. The rooster killed the officer, no person did. For comparison, here are the homicide states of Washington State. Second degree homicide is defined as:
A person is guilty of manslaughter in the second degree when, with
criminal negligence, he or she causes the death of another person.
A noticeable difference in the laws is that in Washington, "causing death" is the defining act, consistent with the definition of homicide as
the killing of a human being by the act, procurement, or omission of
another
In the Philippines it is "killing another", not "causing the death of another". This document from the Dep't of Justice (the Criminal Code of the Philippines) states that as a general principle of Philippine law that
Only intentional conduct is punishable. Negligent conduct is
punishable only when specifically provided under this Code or other
laws.
Intent is therefore an implicit element of the crime, and because negligence is not included for homicide, a negligent killing is not a homicide. Given all of this, the law would not classify this as homicide, given the facts as reported and the improbability that anyone intended to cause a death.
However:
The offender shall be responsible for all the effects arising
from the commission of illegal acts.
The cock-fighting event appears to be presently illegal, there being a covid-related ban on cock-fighting (which is not generally illegal). I will assume that the event was in fact illegal, in the legal sense, though that is not guaranteed. Crimes that could be charged are (Art. 365) punishes the crime of imprudence and negligence:
Any person who, by reckless imprudence, shall commit any act which,
had it been intentional, would constitute a grave felony, shall suffer
the penalty of arresto mayor in its maximum period to prision
correccional in its medium period
or, with a lesser penalty (up to 6 months) for "simple imprudence". Since The Philippines is a civil law jurisdiction with a US case law veneer, it is hard to be certain, but it is likely that this is at least "simple imprudence".