Would adding calcium to feed short term be harmful to my rooster?


Jul 9, 2021
SE Georgia, USA
Two of my 6 month old hens/pullets have been laying soft, shell-less, or thin shelled eggs over the last week or so. Both have been laying for about six weeks, only seeing the shell issues for the last week or so.

I’ve been feeding them Purina Flock Raiser until recently. Hubby bought a local feed from a local feed store. I’ve been mixing it half and half with the Flock Raiser in order to use it up. They have plenty of oyster shell free choice, but not sure if these two are eating it.

My question is: would adding a calcium booster to their feed short term be harmful to my rooster?


Jul 9, 2021
SE Georgia, USA
Not short term, he'll be fine. I'll bet he eats the oyster shell sometimes too, mine did.
Chickens seem to favor egg shells better but oyster doesn'tdissolve it's easier to store.
Yes, he does lol

When we have way too many eggs, I put a few in the blender (shells and all) and then scramble for them.
I’ll also start saving the shells from the eggs we eat and feed back to them.


Scarborough Fair
5 Years
Jul 3, 2016
WA, Pac NW
My Coop
My Coop
If you know which 2 pullets are the problem birds, you could also separate them and give them a private breakfast, to boost their calcium levels without impacting any other birds.

2-3x a week serve a small bowl (like 1 Tbsp is fine) of wet or fermented feed with oyster shell mixed in. If they do not like chunks of oyster shell, crush it up or use the powdery remnants from bottom of the bag. Should only take them minutes to eat and after that they're free to go.

Assuming the issue is simply insufficient calcium intake, you should see results in a week or two, and you can try reducing it to 1-2x a week and should hopefully continue getting good results.


Free Ranging
Jun 7, 2020
North FL Panhandle Region / Wiregrass
The studies I've read show higher incidence of clinical signs of calcium overdose in roosters as quickly as 12 weeks, when offered at the beginning of their life cycle, though obvious visible evidence is often months later before being noted. Grown birds are a little more resilient and likey get a bit more time before gross clinal signs are evident in the liver, kidneys, etc.

I can't give hard numbers because it depends on the dosage, the time period, and to some extent the breed and bird. AND the feed.

Short term, you are fine. If you don't plan on keeping the roo for years and years and years and years (i.e. he's not the beloved family pet), you have greater risk tolerance. Even a rooster developing a bit of gout and lesions on the internal organs may appear "normal" externally, because the onset is slow, and you never see the bird's full potential - but as I said, that takes many months at high dosages.

Short term (say a week or two), you could treat everyone to see if that helps your two softies with virtually complete confidence there would be no evidence whatsoever of the briefly high dosage. But you are definitely better off if you can separate the two birds in question and oral dose them. You might also consider offering crushed raw eggs. I've found my roosters largely ignore the shell (after the initial try it and find out, of course) as will most of my girls, but my birds feeling a craving (and my ducks - its always the ducks) will select shell over contents until their cravings are addressed.

One md-lg egg can be offered daily, as a treat, for every 5+ birds in the flock [warning, math!] together with your normal feed regimen w/o risking imbalance in the diet.

Ebony Rose

12 Years
May 26, 2009
David, Chiriquí, Panama
In addition to making them scrambled eggs with ground up eggshell, you can add enough of their ground up feed and a bit of baking powder. Fry this up like a pancake and serve after it's cooled down. Makes for another texturally pleasing treat that won't break their diet.

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