My male swan seems a bit off in one leg, as though he is reluctant to put full weight on it and can't fully support himself on that side. There's a more than a usual "dip" in his gait when that leg hits the ground.

He also struggles sometimes to stand upright from a resting position. He swims fine and will walk around once he gets going, just wondering what some common leg ailments might be; perhaps a sprain?

Thanks in advance,

Aelise