We are about to process our first broilers and a few died of heart failure... I witnessed a heart attack yesterday. Pretty violent... I have noticed that the ones who died had combs that were going almost purple, like lack of oxygen. FWIW!
This past week, I found one of my CX roosters just sitting away from others who were scrambling for their breakfast. It appeared to have labored breathing, and his comb was cyanotic. I am a retired physician, and the parallels with humans are very real. I would compare a rooster's comb to the lips of a human in that there is a large amount of blood flow in the skin. If a human is having difficulty breathing, and their is some compromise of oxygenation of the blood, you will first see the lips and skin pale. As their condition deteriorates, and oxygenation of the blood becomes more and more compromised, the lips become cyanotic(bluish purple). This happens because blood with decreased oxygen is darker in color.
So paleness of the comb of a rooster, compared with the other roosters in your meat bird flock, in my opinion, is indicative of some compromise of its cardiovascular system. So, if noted, I would seriously consider butchering as soon as possible. If the bird gets to the cyanotic state, butchering will have to be done emergently so the heart will still be pumping blood. Even then, the blood will not drain as well as with a healthy bird. Also keep in mind that a bird that is in severe congestive heart failure(purple) with have retained fluid in the remainder of the body, so organs could be swollen and more susceptible to rupture. I would consider skinning the bird, harvesting the breast, wings, legs and thighs, and not opening up the abdominal cavity. My bird this past week had a very distended abdomen, which was most likely fluid, as well as food in the abdomen.
I think the key is monitoring the birds for these early signs of cardiovascular compromise, so you URGENTLY(within a day or two if possible) process the bird rather than EMERGENTLY (within a few minutes). This will give you time to withdraw feed, etc. to perform a normal butchering process, and will also reduce your stress level.
All of that being said, this will be easier to do in the roosters as opposed to the pullets, because their combs are pale to begin with. I would be willing to bet, however, that there is a disproportionate number of roosters with congestive heart failue compared to pullets, because they grow more quickly.
Just my two cents worth.....
