my girls are getting layer feed and scratch grain and leftover veggies and peelings. I used a few pullet eggs yesterday and those shells are really hard to open. otherwise the eggs are good and the yolks are very orange
If your worrying because you think that your chicken's egg shells are too hard well than worry no more! Your chickens are healthy and you should be proud of it!
Those pullet eggs can have pretty thick shells. I'm not sure if it is because their internal egg laying factory has not worked out the kinks yet or if the shell gland is making enough shell material for a full sized egg and the egg is so small. But I have seen thick shells given as a reason for some problems when trying to hatch pullet eggs, so evidently thick shells with pullet eggs is pretty common.
I've wondered about that at times too. Sometimes my hens' eggs have really hard shells and particularly thick inner membranes. On the other hand, there are times when our flock has had a few members that lay eggs without shells (membranes intact) or with very weak shells. I have always fed the same basic rations and nothing about their environment changes except the seasons! The only thing that changes is the birds. We tend to re-home the hens that have spent one winter with us and raise new replacement chicks for them each Spring. A few select "pet" hens stay with us each year. But generally, 95% of our birds are new each Spring.
I have found far fewer egg problems with the standard heritage-type breeds...RIR, barred rocks, sussex, delawares. The hybrids are different. I find more odd eggs...misshapen, no shells, tiny, ginormous, etc... And we have had a tiny bit more reproductive problems with the hybrids such as internal laying (usually from a hen that has started to lay eggs with no shells) and prolapse (usually those that have layed ginormous eggs).
Be happy for those "hard to crack" eggs (especially when they're in your pocket!)
They put roughly the same amount of calcium into any given eggshell regardless of egg size. That makes the pullet eggs have very thick shells. As the eggs get larger the shells get thinner.
I was wondering the same thing myself. Sometimes I swear I could throw it on the floor before it would crack and other times a tiny tap on the bowl I'm using shatters it.