I've had success with repairing slipped tendon on guinea fowl and silkies. If it is a genetic defect, there's really nothing you can do, but if it is an injury and is caught pretty quickly, it is repairable. One of the difficulties is determining whether or not it is actually a slipped tendon or some other condition. A slipped tendon is painful, and the babe will hold the leg up because pressure on it hurts and causes the joint to swell. If left very long, the joint will "freeze" permanently in that position. If both tendons have slipped, it will "walk on it's elbows." Untreated slipped Achilles tendon is virtually a death sentence because it can't keep up to get food and water, can't fly, and can't avoid predators. The first symptom I've noticed is almost constant crying with nothing visibly wrong. After awhile the joint will swell, which makes a cure more difficult. To test for a slipped tendon, gently, but firmly hold the joint beween your thumb and forefinger and roll it back and forth. If it is a slipped tendon, you can feel it pop into place and back out. A rotated femur is often mistaken for a slipped tendon, and there is no cure for that condition, except possibly surgery.
After working with only partial success with the first one using a process developed by a peafowl fancier; in frustration, I slipped the tendon in place and wrapped a very narrow strip of DUCT TAPE around and around the middle of the joint, on top of itself, making sure the initial wrap was firm enough to hold it in place. If done properly, the joint will still move normally, and the babe doesn't need to be isolated from the flock, which is stressful for it. If it was caused by an injury, it only takes a few days for it to heal. The first time I did this, I worried that the duct tape would harm the skin and was prepared to use mineral oil to release it. However, the natural oils in the skin made it slip right off with no damage. Since that first one, any time I know it is a slipped tendon, I immediately wrap the joint in duct tape. After several days, the tape will loosen and fall off, generally with a successfully repaired leg. I've had several permanent cures and have several friends who've also used this method successfully.
I think the most common cause of slipped Achilles tendon injury is insecure footing caused by too slick bedding material; often newspaper.
