We all know that calcium is required for egg shell production. If we have a hen that lays soft or thin shelled eggs we boost her calcium intake. So what should we be giving our flock to assist our girls to make strong, healthy egg shells?
More egg shells, of course. I ask my egg customers to return their clean dried egg shells, then crush them up and offer it separate from their manufactured feed (roosters don’t need additional calcium). It’s a great source of free calcium.
If you’re thinking about how to tweak their diet foods that are high in calcium include: seeds (poppy, sunflower, chia), dairy products like cheese and yoghurt, fish, beans and lentils, nuts, dark leafy greens, broccoli, arugula, okra, edamame, tofu, sweet potatoes, oranges and butternut squash.
The problem with some of those foods is they also contain oxalates and phylates, naturally occurring compounds that bind to calcium, inhibiting some of its absorption.
Spinach is naturally high in calcium, but it’s also high in oxalic acid. The body is unable to process all the calcium it provides. Other foods that contain oxalic acid include beet greens, rhubarb and sweet potatoes. Choose low-oxalate greens, such as kale and collard greens.
High phosphorus and high-fiber consumption can also interfere with calcium absorption, as can iron and substances called phylates found in seeds, nuts, grains, wheat bran, beans, seeds, nuts, and soy isolates.
Oxalate and phylate rich foods bind the calcium of other foods when they are consumed at the same time. When calcium is bound, the body can’t use it and it gets flushed out.
Don’t throw the baby out with the bath water. Though these foods might not be considered for their calcium value, they do provide other nutrients and minerals that help the body stay healthy.
So how do we feed our flock nutrient rich foods that also might inhibit calcium uptake?
Some things like spinach, beet greens or citrus fruits are healthy, but should be fed in moderation.
Or if you’re feeling particularly dedicated to the nutritional intake of your birds you can do a bit of juggling by feeding calcium rich foods two hours before, or after, calcium binding foods.
This allows for the full absorption of all the nutrients our birds need without interfering with their ability to absorb critical elements like calcium. It means they can have their cake and eat it too: all of their favourite things, just not at the same time.
Note: you can get too much of a good thing. High levels of calcium can cause accumulation of uric acid, leading to kidney issues, including gout.
You can monitor your hens’ needs by inspecting their eggs: soft-shelled or thin-shelled eggs are a sign that they need more calcium. Thick shells or ones with bumps, which are easily scraped off with your fingernail, are indicative of excess calcium. Adjust their intake accordingly.