Had him marked with a zip tie. Looked as though he was taking another turn for the worse so I culled him today. For a bird that was a definite goner a few days back I was able to keep him up and running for a few more days. He had a small amount of fluid in him, so I think it was either lungs or heart that was finally his issue. No necrosis in the inner rib meat, comb was looking more cyonitic.
Overall, reasonable bird, weighed in at 7lbs dressed, meat and skin appeared normal after processing. He bled out fairly well. Tomorrow they are 10 weeks old.
I wasn't thinking that it would be a cure, but more of a stop gap if there were a number of birds taking a turn within a few days left before processing. Thankfully I pick up the processing equipment on Friday.