Excess calcium and kidney damage

Here are a couple of articles about kidney damage in chickens, caused by excess calcium in their diets.  Both articles have graphic photos of chickens' organs that have been damaged by excess calcium, so be warned!

The basic summary of both articles is that if you feed layer's feed (or other high-calcium feed) to chicks or young pullets who aren't close to laying, you run a high risk of long-term kidney damage in those birds.

They also both mention that if you can acidify the urine of the birds, you may be able to reduce the damage and/or relieve or slow down the resulting problems.

I have put these articles here because I think they will be very handy to refer to, when people ask why there are different kinds of feed for different ages. 

They may also help people to understand the risks involved in adding additional calcium in the form of limestone flour or shell grit into the chickens' feed. (Note: there is no evidence that excess calcium is caused by having shell grit available in a seperate container for the hens to take as they choose.)

The first article is from World Poultry. "Kidney Damage is Emerging in Laying Hens"
http://www.worldpoultry.net/chickens/breeding/layers/kidney-damage-is-emerging-in-laying-hens-8719.html

The next is from Hy-Line International. "Avian Urolithiasis (Gout)"
http://www.hy-line.com/userdocs/library/0_Avian%20Urolithiasis%20Eng.pdf

Both articles use quite 'scientific' language and are obviously aimed at big commercial operations rather than home keepers of small flocks, but the same basic principles apply.

Thanks Lindeggs.  They look really interesting.