Saturday, February 16, 2013

Calcium: Mixed Flocks vs. Mixed Feeds

By Leigh

As chicken keepers, many of us worry if our flock is getting enough of the necessary minerals, vitamins and nutrients. Modern, pre-mixed feeds tend to lessen that concern for many, yet if you have a mixed flock, these premixed feeds may present another danger.

For those that have a flock comprised only of laying hens, Layer Feed may work just perfectly. For those who have roosters and younger birds that are not yet laying mixed in with laying hens, premixed Layer Feed may not be the best thing for your whole flock.

The reason behind this conundrum is the calcium content of commercial Layer Feeds.

The calcium content in chick starter / grower feeds and general flock feeds usually falls between 0.5% and 1.5%.

The average calcium content of Layer Feed ranges from 3.25% to 4.8%. If a bird is laying regularly, these calcium levels are fine as the calcium is used to create the shell of the egg… but for any bird that is not laying, these levels may be too high, and might actually cause harm to some birds.

If a chicken is not laying and using excess calcium to produce egg shell, the kidney must filter out the excess calcium. Over time this can cause kidney failure.

Too much calcium, or Hypercalcaemia, can also result in calcification of the soft tissues and organs (including the liver and heart), pancreatitis, egg binding, dry skin, appetite loss, lethargy, confusion, depression, slowed growth in pullets and cockerels, dehydration, diarrhea or constipation, and even death.

So how do you feed a mixed flock of chickens without causing calcium deficiencies in laying hens, yet not overdosing young birds and roosters?

Many long-time chicken keepers who use commercial feed use “Grower” or “Flock Raiser” products designed for non-laying birds aged 10 to 18 weeks, and then offer free-choice oyster shell. Chickens won’t overdose themselves on calcium when it is fed free-choice. You will almost never see a rooster picking through oyster shell unless he just saw a bug jump into the dish.

It should also be noted that vitamin D3 is absolutely essential to the proper absorption of calcium. Most living critters obtain the bulk of their D3 through sunlight – so make sure your flock is getting plenty of rays! Not enough sun can cause laying hens to be unable to absorb the calcium in their diet. This can be just as dangerous to laying hens as too much calcium in the food would be to non-laying birds.

I will also note that other long-time chicken keepers report no ill effects from feeding layer feed to their entire flocks for many years.

Every bird is different and every breed of chicken is different. Some may be more sensitive to higher calcium levels, and others may be just fine with it. Those that get tons of natural sunlight may properly absorb much higher levels of calcium than those that stay inside for long periods.

My personal philosophy is that if I can do something that may help avoid long-term health issues in my flock without additional expense, it’s worth doing. I have always offered free choice oyster shell anyway, so switching feeds to the lower calcium feed made sense in my case. You be the judge and do what will be best for you and your flock.



And special congratulations to the winner of the Nest Box Blend Giveaway: Marianne Cowan. Please email us at, Marianne!



  1. Good post again! I'm with you - I want to give the whole flock the best opportunity to be as healthy as possible.

    I use a feed that is safe for all ages then supplement the various age groups appropriately.

    My feed contains lower calcium level and I give calcarb free choice on the side.

    Another issue is the protein level. Chicks need a higher level of protein than the older birds. Since I have my feed formulated for the whole flock, I have the protein set at the adult level. Then I give the "littles" additional protein mostly in the form of raw meat. (Usually ground venison or beef and occasionally some chopped liver.)

    So far this has worked out wonderfully as I have to purchase a minimum of 300 lbs of feed (which volume I share with another lady in my area) since I have it formulated the way I want it at a local feed mill (no soy, no GMO). That keeps me from having to get large quantities of several different formulas.

    Thanks again!




  2. Whoa...guess that comment really wanted you to know who left it! LOL
    LM (Again)

  3. Great.. Thanks.. for directing me.. to this .. I was curious..
    I got my 2 jersey giant Roo's before getting chicks.. I really didnt know what i should get for them.. untill the chicks catch up. The man at the store was not familier either.

    I purchased Layer mix -there is powder in it, and it dose not look as good as the photo i saw on BYC.. of the 2 bucket system. I wonder if the powder is what clogs up the 2 bucket method.. and gives the milky consistancy which i have difficulty filtering too.
    I like the recipie here.. but will have to wait till the rest of the flock & maybe friend to go in for the quantity... Is there a mix the feed store might be better for me to try , rather than the Layer rations.?. I'm totally lost in a whole new vocabulary to learn .. thanks for your help..

    1. Are you buying bagged feed or do you have the feed store make it to order?

      If is a bagged feed and you want to give the whole flock the same thing, you would get the all-flock which has a mid-range protein and a lower calcium.

      Then put out the calcarb or oyster shell free-feed and give the babies some extra protein!

      If you have it milled to order, I can send you a list/percentage of what they make for me.

  4. Great post. There is so much confusion about what to feed a flock when you've got nonlayers in with laying hens. We have ducks as well so that makes it even tougher but I do what you suggest here. And it's true the 'littles' and the roosters and drakes NEVER eat the calcium...unless as you say a bug flies in or a kernel of cracked corn ends up in there!
    Fresh Eggs Daily

  5. Now I wonder if I am giving my laying hens too much calcium! They get organic layer pellets, plus free choice oyster shell, plus yogurt once or twice a week. But I guess if it was too much, they would just ignore the oyster shell, right? One of the reasons I give them yogurt, besides the fact that they love it, is because I give them Fertrell NutriBalancer in the winter time. It's powdery, so I need something moist to mix it with. They often stay indoors because of the snow, and even when they go out, the sun isn't strong enough here in Maine in the winter time for them to make vitamin D. I noticed that despite all the calcium they get, when they didn't get enough D, the shells started getting fragile. Since going on the FNB, their shells have been fine all through the winter.

    1. My feed has the fertrel too. At this point I ferment the feed so everything gets eaten with no problem. BUT...when I wasn't fermenting the feed here are some things I did that makes them be able to use the powders:

      When they dry feed:
      -The fertrel and fish meal was mixed in with the regular feed. I'd gather up whatever powdery stuff and grains they didn't eat then put it into a pan about every other day and pour over a little melted lard, mix it up then put it out for them. The melted lard was a suggestion from a long-time chicken owner and show man who said he fed lard to his chickens to help condition feathers and give them healthy skin. They love it and they use all the powders!

      -Sometimes I'd let the dry feed soak overnight in a mixture of milk and a little ACV. Also causes them to be able to eat it without losing the powders and the soaking overnight helps to break down the phytic acid in the grains in the feed making it more bioavailable (they use more of the nutrients in the feed)

      -Sometimes I'd mix in a little yogurt or whey with the dry feed(leftover from making cheese so most people don't have that).

      You could also just ferment your feed...that takes care of it too!

      You're right on the vitamin D! Have to have it to properly digest the calcium. Something that will help with that in the winter is to feed ORGAN MEATS. Liver, heart. You can just get some calf liver from the grocery and chop it into small pieces. Once the figure out what it is, THEY'LL ABOUT KNOCK YOU OVER to get at it every time you bring some out!


  6. I'm glad you touched on this subject. So important!


  7. Re: fermented feed. Do you mix every batch separate? or, just add to what's left over? And, what do you use to feed it to the chickens? (what kind of feeder)

    1. Gale - you can find the answers to most of your Fermented Feed questions HERE.
      To briefly answer some of your questions, you'll want to use either glass or plastic feeders. Keep your fermented feed batch going indefinitely by simply adding more fresh feed to it each day. :-)

  8. My girls have stopped laying since molting and less sun. I took out the calcium for now and have them on all flock even though I have only 8 hens. I may give them some chick food for extra protein. Thank you for the advice.

    1. Judy - you are very welcome! Just keep oyster shell available for them to pick through as they like. In fact, you can keep them on the all flock feed if it saves you money to do so.


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