Nearly all snakes are going to have parasites, simply due to the fact that they eat whole prey. Rats and mice commonly carry parasites that then live in the snake when eaten. I would say that 90% of the snakes that we do fecals on have some kind of parasite. Ones that eat live prey are going to be more susceptible than ones that eat F/T, because the freezing kills some of rodent's internal parasites. Freezing doesn't kill all of them though, and the length of time the rodent is frozen also plays a part in it.

But you have to remember, just because a snake has parasites, doesn't mean it has a problem. The severity of the issue will depend on the snake's health, age, immune system, etc. For example, if you have two snakes the same age, but one is fed properly and housed in a proper environment and the other is underfed and/or housed poorly, the one that is in better health could deal with the same number of parasites that could potentially kill the second snake.

From my own personal experience, and from the samples we get in the clinic, the snake poo that looks like dog or cat poo, i.e. firm, holds a shape, some odor but not horrible, rarely has parasites. The poos that are mushy or stinky often have parasites.

Another symptom of having problems with parasites is refusal to eat. Not saying that it would be the reason for yours, but it's something we consider with snakes.