Limestone

[Gray Ghost]

I live in an area where the bedrock is limestone (calcium carbonate) and the soil is sandy with a lot of ground up limestone in it. Will this limestone sand serve as an adequate calcium supplement or should I still provide oyster shells?

Also, is beach sand a good size for digestive grit? I have a pretty much unlimited supply of limestone sand and gravel for free.

GG

 

[Akane]

I would think it would provide plenty of calcium so long as chickens' digestive tracts can break back down the calcium carbonate. Just because it's made of the same material doesn't mean it reacts exactly the same. Limestone is a very compressed version of calcite (calcium carbonate) which makes it only partially dissolve in water instead of completely break down like calcite rock would. It also can contain various levels of contaminants so in some cases they would be getting more of other minerals than they would calcium.

The size of the particles for grit is not as important as it's make up. It sounds like the sand in your area is made of soft rock which would not grind well. They would have to use a lot of it because it would grind itself up quickly and pass out of the digestive tract. Granite is used because it's hard enough to last a long time and break up other hard materials like the limestone and oyster shell.

 

[gryeyes]

Beach sand, if it's along the ocean, might not be so great due to the salt in it. But if it's lake (freshwater) beach, then I guess it should be okay.

 

[Organics North]

If you ever get over to Wausau/Mosinee area, you should be able to fill a few sacks up with rotten granit. (When you see pink or salmon gravel on the side of the road that is the local rotten granit.) Small size makes great grit for the birds. I bet some course Lake Michigan sand would work too.

Your local limestone might be OK in summer, but a bag of oyster shells at Farm and Fleet is like only $9 and lasts a very very long time. I offer it free choice to the birds.
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