Okay, it looks like it could be worms, enteritis, or injury.
I guess I'd look for signs of worms first, and try to observe any other symptoms next. Here are some of the links I used:
http://edis.ifas.ufl.edu/PS044
This has a chart that's particularly helpful.
http://www.ces.ncsu.edu/depts/poulsci/tech_manuals/small_flock_resources.html#problems
This has a zillion helpful links.
This is the best source, if you know what you're looking at, but it can help to diagnose if you have a lot of time.
Good luck!
I guess I'd look for signs of worms first, and try to observe any other symptoms next. Here are some of the links I used:
http://edis.ifas.ufl.edu/PS044
This has a chart that's particularly helpful.
http://www.ces.ncsu.edu/depts/poulsci/tech_manuals/small_flock_resources.html#problems
This has a zillion helpful links.
This is the best source, if you know what you're looking at, but it can help to diagnose if you have a lot of time.
Good luck!