Duck with odd injuries, x posted from duck thread. Please help.

So, I was given this duck. The old owner said it just started acting funny, falling down when walking, etc. I noticed the head wound the same day I got him - I'm assuming the other birds he grew up with had been picking on him - and I've separated him from the rest of the flock and have been giving him daily baths and feeding him the rickets diet, thinking it was a combo of rickets and pain from the head injury.

The head injury looks tons better, but today I noticed him biting at the spot on his chest. Here is a pic of the head injury, and then the chest injury.






At this point, I'm not sure WHAT to do about this duck. I've had him for about a month now, and he just doesn't seem to be getting any better. He was free, so I'm doing all I can do before having to call in the vet, and I've worked really hard trying to get him healthy, but I'm obviously not helping him much. Any suggestions or knowledge on what is going on would be appreciated.