Suppose I left some chicken in the freezer for 8 days and the freezer was set to go from 0c to -5c over those 8 days. Since the air temperature was still below 0, is it safe to eat that particular chicken? As far as I'm aware, bacteria only becomes a problem at higher temperatures. If not safe what might the problems be?
According to FoodSafety.gov, poultry can be stored frozen for 9 months or more, but frozen storage should be below 0F (-18c). The issue is that in a freezer set to 0c, there's still a good chance that the temperature fluctuated slightly above freezing in that time. The storage time for refrigerated poultry (below 40F/4c) is only one to two days, so your answer probably lies between those two somewhere. Due to the low temperature, but possibly freezing and thawing, I would think that you would face a decline in quality more than a biological threat.