Obviously not talking about cows, pigs etc, but fresh fish, rabbits etc are easily accessible within hours of catching and killing them. I find most fish is best eaten before it goes into rigor mortis, and that I assume that this preserves the glycogen when you eat it? Does it exist in significant amounts, is it damaged by cooking, and can it be digested and metabolised as an energy source when eaten? Can it be preserved by rapid freezing?

many thanks in advance!