My duck has a really bad limp, it started in the morning when I let him out to free range. He always runs out in the morning but this morning he could barely get up, he tried to run but he kept falling. I looked at his foot for signs of bumble foot but there wasn't any bumps or swelling. The next morning he was even worse, I had to carry him to his pen outside because he wouldn't walk without falling with each step. When he was in his run outside he just stood there with his leg straight out, he wouldn't bend it. I noticed a little smelling at his knee and it was warmer then the other leg. I will try to get some pictures but untill then does any body know what I can do or what it could be? Please help!