This is a copy paste about shell less eggs.
Chickens need a lot of calcium to create good, hard shells, so most incidences of shell-less eggs in an adult hens are related to not having enough calcium in the diet. Young hens may lay a shell-less egg or two right as they begin to lay eggs for the first time, before their systems have "gotten into the groove" of laying. If your girls are on a proper diet of lay ration and have oyster shell free choice, they should have all the calcium they need. They also need Vitamin D and a proper balance of other vitamins so they can process the calcium. Lots of snacks or scraps can throw off the nutrient balance of their diets or give them too much salt.

Disturbances at night while they are sleeping--a predator prowling around, or a big storm, for example-- can also sometimes upset their system and cause shell-less eggs. If that is what's happening, some of the other girls' eggs may have bands or "checks" on them, as the laying process was disturbed briefly before resuming its normal course. If disturbances are the problem, when they cease, the shell problems should cease, too.

Another possibility has to do with the salt in their diet. Too much salinity can cause shell-less or thin-shelled eggs. So, sometimes if they are drinking water that is highly softened, it can contain a problem amount of salts for them.

It could also simply be a defective shell gland; it that is the case there is nothing to be done about it.

Lastly, infectious bronchitis can also cause thin shelled eggs, or eggs with no shells. Chances are good you would have noticed respiratory symptoms. If you suspect your chicken has a case of IB, you should get her to a vet for a diagnosis immediately. There are some other illnesses, such as egg drop syndrome, that could cause the same thing. If you have eliminated everything else, your vet may be able to help you.

We do have dogs and armadillos around alot. I was told the laying mash had all the calcium the girls need. We do give them chick weeds once or twice a week. They have no grass to eat until it gets warm. They are two years old. I will get some oyster shell calcium. Thanks for the advice.

Although the chicken pellets have calcium in it I add a handful of oyster shells to the chicken feed daily.

I also feed my chickens greens.
Cut in thin slices romain lettuce and watercress.
I also offered soaked mung beans ( soak until they are soft usually takes three days). Cucumbers , apples, and berries when in season. They love fresh blueberries.
Pumpkin, cliantro and eaten . They do not like parsley or bananas.

I found rubber eggs and occasionally an unshelled egg in the nesting box. The rubber eggs concerned me cause it meant a hen had a bad ova system. I also have a hen that lays the hugest eggs. I am unable to close the egg carton due to size. I believe this hen will not survive cause her eggs are so huge and she screams when she passes one.
Offer some greens while waiting for Spring to emerge.

They get red sorrel almost every day, which they truly love. We also have one chicken that lays a super big egg and it is hard to close the egg box. I only hear her cluck with joy after she has laid an egg. We started giving them oyster shell calcium and the shells are harder.

This is just a thing, my chickens get shells all the time, and to us it is just a 'wow' moment. Sometimes stuff happens. No big deal.

Cheri, love the shelless eggs, the super long weird eggs, all the cray things chickens do...

It stopped happening awhile ago. We get one very oblong egg. We had to separate the smallest chicken from the others. They were pecking her and chasing her around the coop. She is quite happy being alone. She lays the darkest brown eggs now with a very hard shell. Same diet as the others. Go figure.