Possibly injured and now missing?!

[ElsieBird]

Earlier today one of my roosters was picked up by my fathers dog. He was missing a few tail feathers but didn't seem to be severely injured. he was walking around and all seemed well. But tonight when I went to go feed he is now where to be found. Do chickens wander off to die? Or did he just run away? He is a really friendly chicken, loved to be held. It is unusual for him to just leave. Any suggestions?
I was away for a wedding and my two roommates where watching them so I din't actually witness anything.