oh, and from my own experience, more watery droppings are relatively common in association with extra water consumption during hot months with high protein. Not normally concerning.
When you butcher one of the cockerels, pay close attention to the levels of fat in the organ cavity, and around the heart, liver condition particularly. Excess fat can contribute to purplish/blackening comb and similar circulation problems at the extremities - but unless the bird is quite skilled at picking out the "candy" in the scratch, that's likely not the cause - just something to be alert to when you do butcher.