The diet of the sugar glider in the wild is based upon seasonal availability and luck in foraging. It is not necessarily what is best for them, it is simply what is available to them.
In my studies of marsupial nutrition, I have not come across any studies showing that gliders in the wild eat chickens. In fact, the last book I read showed that they killed birds just to take their eggs - they never ate the birds themselves.
I am always interested in why people want to mimic diets an animal eats in the wild. This is not something that I personally have any desire to do. I think of other animals - lets take dogs for example - dogs (and sugar gliders) can survive in the wild by hunting and foraging and eating anything they come across that is edible. One of my dogs was rescued from just such a situation. She was alive, but thin and full of parasites and not healthy. But, she was surviving just fine. I want more for her. I want better for her.
The overall life of a sugar glider in the wild is a harder one with a much shorter life span than those in captivity. Though there are stressors and problems that come with captivity, one of the improvements we can make is to their diet. So, I feed them the best, most well rounded diet I can. This means that I'm not mimicing their diet in the wild....I'm doing better.
That's my 2 cents on it. I'd love to hear others. I see this come up a lot in terms of diet and of enrichment opportunities. Every time I see it, I don't see compelling reasons shared to try to replicate these things in the confines of captivity. I can think of a few compelling reasons myself, but I would love to hear the reasons that others have.
If you strongly desire to utilze a more raw/natural diet, then you might try contacting Kelly (screen name is khigh) and talk with her about her diet.