Without examining him, the eating and pooping seems normal. If he is eating a large amount of food then the amount of poop should be comparable to intake. Cygnets eat a lot of food and poop ALOT! Eating and pooping are usually signs of good health because once a bird stops eating or pooping, it is an indicator that something is wrong and the bird needs to be seen by a vet immediately. Birds go downhill quickly. We are not sure where you are located, but if you are having hot weather, this could be the reason for the sluggishness. Swans are generally a lazy bird and will stay in the same area if there is an ample amount if food. Coupled with hot temperatures, swans may get lazier and choose to eat and waste as little energy as possible.

Having said this, if you are concerned that there may be something abnormal occurring, we would strongly suggest that you have the cygnet examined by an experienced waterfowl/bird veterinarian. Again, birds can deteriorate rapidly if something is wrong with them. If there is indeed diarrhea, then are any number of causes which can be considered from an infection to parasites. The Regal Swan