Hi everyone, I have a male rabbit, neutered, unknown breed (maybe flemish giant mix... he's pretty big, rescued as a meat rabbit) about 2 1/2 years old. Today was the first nice day of spring, so we took him out to a safely enclosed area in our backyard for him to play. He loved it and spent most of the time out there running and binkying. After about 2 hours I brought him in, since I didn't want to suddenly strain him with all the exercise and I had to leave for an appointment soon anyway. I cleaned off his feet (which he didn't like much) and let him be. I left and came back about three hours later to give him dinner and found him hopping really stiffly. His hind end was lifted really high up, and he didn't put his back feet flat -always raised up like he was keeping weight off his heels. He otherwise seems fine - he ate dinner happily, had some hay - but doesn't seem to want to move much. No teeth grinding or hunching while laying down. Is it possible he's strained a muscle and feels stiff or possibly injured his hocks (he has some light sores from being on less-than-ideal carpet, but never acted this off) or could this be something more serious? Thanks for all the help, it's greatly appreciated!