It sounds as if the veterinarian is on the proper course in providing pain relief and precautionary infection control. A 10 hour ride is extremely stressful. Was the swan in a container that the swan could not move around, had too much room and was able to flail around and hurt it's legs or wings, was the swan on a slick surface, was it provided fresh water and food during the ride, was the swan in a carrier in the back of a truck open to wind, heat or cold or in the back seat of a vehicle in which it could have gotten overheated, were gas fumes or car emissions present near the swan while being transported in the vehicle? Any of these could cause stress. Additionally, if the swan was less than 7 months of age, separation from its parents and siblings could be a major issue. The Regal Swan