I agree. There are many other ways to provide proteins for the birds than hanging a rotten carcass over their living quarters...what folks fail to realize is that rotting liquid, filled with the bacteria that help in the decaying process, is dripping into the soils there. Those are the very pathogens one doesn't want thriving in their livestock feed, soils, environment and botulism is a very quick bacteria to grow and quick to kill animals that do not have the digestive acids that can handle it.
I found that out this past fall in a roundabout way. I had obtained a pen of mixed breed roosters for the purpose of eating. They were penned for a few weeks and fed some healthy food to clean out their systems. All birds active, bright eyed and healthy. The day I processed, I let two young roosters loose with my free range flock to keep them awhile for the purose of putting on more weight. I didn't really think about the fact that these roosters knew nothing about foraging. When I disposed of the fresh remains of the process over in the woods, I had no fears of my chickens getting into the pile...usually they wait for the tender bits that I throw them during the processing but I've never seen them pick the gut pile as the rest of the tissues are long, stringy and not easy to ingest.
I wasn't thinking about the two inexperienced roosters not knowing how to forage on chicken appropriate foods out on the pasture and later saw them over at the gut pile. I didn't think much about it until that evening when I saw one of them lying down in the yard. I went to examine him and he got up and took a few wobbly steps, but clearly was having some issues. I left him be to see what would transpire...later I found him lying down again and he didn't get up that time, so I set him on his feet and encouraged movement...he was having some problems in his nervous system, couldn't maintain balance and had tremors in his muscles. I saw his crop was a little distended and green blow flies were lighting on his body, I took a whiff and he stank like rotten meat.
That fast...from around noon to 4 pm that evening, he had an infection. The tissue he had picked off that gut pile was fresh, not rotten, but when it hit his crop it immediately started to rot and the bacteria there were sending out toxins. I milked his crop and greenish brown water came out that stank like a rotten carcass. A long piece of windpipe came out and a stringy piece of gut also came out. But it was too late for that bird...he was fevered, couldn't stand any longer and the flies were blowing him like he was already dead. I dispatched him and disposed of him where the other birds would not venture, then moved the gut pile to that location also. The other young rooster may not have gotten gut pieces that hung up in his crop and couldn't advance, as he did just fine, so it wasn't the nature of the meat that caused this infection, but just getting the meat lodged in an airtight, warm place that can breed botulism. His symptoms were much like botulism, so I just assume that is what he had.
That was the very first time I've had a bird get sick while in my care in 37 yrs, so that impressed me greatly as to how dangerous botulism can be for an animal that small. Nothing to play with.
http://www.defra.gov.uk/ahvla-en/files/pub-vet-botulism.pdf