Mochi Please

Mochi, please stop making me worry about you so much. Discovered Mochi was limping when he went to go to bed last night. We've separated him and brought him inside to rest. He doesn't seem to have any other symptoms, and his other leg is fine. When he tries to walk, he only takes one step and stops. Its hard to see anything coz he has so many feathers on his feet. Could he have a sprain? What should we do?