I have a bird. His name is Peepers. Peepers is a six year old parakeet. We used to be able to let him fly around the house. Unfortunately, we can't do that anymore because once, when he was about four years old, we let him out. He was flying around happily when he tried to land on the fast moving fan. He missed the fan. But, the fan almost cut his leg off. He had a deep cut in the center of his foot. Luckily, it didn't stop Peepers from walking.
For weeks, he tottered around his cage clumsily. Sometimes he fell off his branches because his foot didn't give him a good tight grasp.
About a month later, he recovered and was well again. We still let Peppers out but, only when the fan is not running.