When you say the consistency of pea soup, it's not that color right? Are there distinct brown(primarily) and white parts? A picture would help.
Do you have any of her siblings to compare her to? Easter Eggers can potentially have a whole bunch of genetics mixed in and there are a few bantam varieties that lay blue eggs. Also, my EEs seem to grow slower than the other types of chickens I have but they end up pretty similar in size when they are done growing.
I would suggest, for some piece of mind, to take a sample of her droppings to the vet for a fecal test. This will tell you if there are any worms or cocci present. Any vet, even one that does not treat chickens, is capable of doing a fecal for them. You might have to call around since some vets won't do them unless the animal is a patient but you should be able to find one. They might be more willing to if you already take your dog or cat to them and they know you.
A note about the results of the fecal test; there are always cocci present in every animal. If they have a good immune system, they will be able to keep the cocci in check. Vets will often tell you the animal has coccidiosis when they only find one or two cocci in the sample. So, if they tell you it's there, make sure you ask how many were present, do some internet research and decide for yourself if it's worth treating at that level of infection.
Hope this helps!