Also I heard that it could be to much calcium in the diet but the chicken is getting these dots on the egg then a day later lays another egg with a really thin shell like paper thin and then lays the next day which could be ok.
What type of food/treats do you feed?
How old is your hen?
Do you provide oyster shell free choice?
It look like it is calcium deposits on the egg. Some causes are disturbances/stress during the calcification process, too much calcium in the diet, not drinking well or having limited access to water and defective shell gland.
Watch to see if she is drinking well, if you provide oyster shell - make it available free choice (don't mix with feed), monitor your flock for signs of stress and take steps to minimize or correct any stress you see. Defective shell glands, there not much that can be done.
Hi thanks for your reply, I'm very new to owning chickens, she is about 10 months old, I brought some grit which has oyster shell in it because of this issue but haven't put it in their food yet.
I'll keep an eye on the water.
How can you tell if a chicken is stressed? The other 2 chickens I have don't have this issue at all.
Offer the oyster shell free choice - put it in a small container in the run or scatter it on the ground. They will take what they need.
Stress can be seen with egg quality issues, going off feed, staying by themselves,etc. It's hard to know when they are stressed because chickens can hide an disturbances well.
Now, any of the above can be a sign of illness as well, so observing the flocks behavior - knowing your hens will help.
Since she is young (10months) she may still be working out the kinks. You mention that she is not consistent with her egg laying - one day thin shell, another normal, another with calcium deposits. Hopefully providing the oyster shell free choice, seeing that she is not being kept away from food/water and no one is picking on her, the problem will resolve itself. Also limiting treats (scratch, corn, etc.) to no more than 5-10% of daily intake may help as well. Offer a small amount of leafy greens, veggies or fruit daily as a treat.
the dots are calcium deposits . They are not harmful, it just means that the hen is having excess intake of calcium. She is probably still working out the kinks as Wyorp rock stated. Give her a few more weeks to sort it out.