They're about 16 weeks. Yes they're past processing time being the place I was going to take them to is no longer doing it. So I'm doing it myself with my brother who's a butcher. They're Moyer crossed and they're gigantic. I had 26 and I'm down to 16. I have been feeding them broiler mash and cracked corn. They're in a 9X8 hoop house tractor that we built. It's weird how it all seems to have started after they got that snake.
My daughter and I process our boys. We just skin them for now while improving our skills. Our first boys were a bit older because it took time to work up the courage to proceed.
I have not heard of Moyer cross before.
Get rid of the corn completely... it is diminishing you whole operation. Most commercial feed are already mostly corn. And depending on the ration you have been using... is actually giving your birds more fat than muscle content, which I'm sure is not your goal. The amino acids help build muscle. Plus the vitamins and minerals help have healthy birds with better immunity. Thereby giving you a more nutritious supper. Extra corn is like a candy bar. Yummy!
Yes, teenage boys will become quite hormonal by this age, and that is apparently too small of a space, indicated by your troubles. If they had some hiding places, it might help. Just some visual barriers. And remember, in your space, you are giving some of that square footage to the feeder/waterer.. thereby having even less area than you think. (I think)
IF free ranging were an option, that's what I would do. Or I would start processing. I start with the biggest bullies. We can only do a couple at a time. But it ALWAYS makes for a bit more peace. Sad thing is that if somebody starts beating up another, other will often join in to raise their place in the pecking order. Guy on bottom with no way to get away will likely be dead, as you've experienced. To be honest, space doesn't matter once they decide it's on. Sometimes it will become relentless chasing and beating. In which case I step in and give the chasing cockerel a little chase of my own with a nice long PVC pipe!

I don't like bullies.

Ever heard the best defense is a good offense? Can't tell you how many times I've seen that be true.
The snake was probably just coincidental.
Are you pretty sure you haven't had any illness leading to weakness leading to the pecking?
Is corn even cheaper than feed? It doesn't seem to be so here. I know the chickens love it and many people feed it. But whole heartedly, nutrition and space are going to be key to your recovery.
Hang in there, we all have things happen and start learning from our mistakes if we can!
ETA: Looked up the birds, and I agree... age could be part of the issue with the deaths you've experienced.