FYI since that last thread I've talked with another breeder with a long string of no kinked caramels who also feeds rodents fed Mazuri 6F. He did mention some kinking his first year but I haven't heard back yet on a request if any other food could have also been used that year. I would suspect that if there is anything about Mazuri that makes it better for caramels it's an accident so hopefully we can figure it out before the formulation changes.
Also, I did find a site mentioning spinal problems in chickens exposed to copper:
http://www4.uwm.edu/cehsc/pilots/projects.html
And here is a recessive human disease requiring reduced copper diet:
http://health.nytimes.com/health/gui.../overview.html
Here is one that mentions Vitamin C deficiency (there is some sort of link between C and copper I don't understand) causing what sounds like kinking in fish:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC339614/
And for good measure here is one mentioning copper deficiency:
http://www.sciencedirect.com/science...661ddf9d30e148