I agree. Not the rooster.question about your chickens, are they allowed to go in and out? I saw the rooster was out, not sure if I saw another one or if the was same bird or not.
That gap in the wood, could allow a predator to get in-mouse, rat, snake, weasel, mink, etc
I would think that the "chipmunk or rat" holes would also allow predators access, unless they have been filled.
I would agree that it is not the rooster
Not sure about the water pathway but weasels will remove the heads.
The holes you called a rat hole is big enough for a weasel.
Unless the young roo is causing the comb to bleed and then they get attacked by all the rest of the birds. But for that to happen more than once???