If they came from the feed store, they are Easter Eggers, not true Ameraucanas. The only place you can get true AM's are from breeders or occasionally a hatchery like My Pet Chicken.
Most of the time they lay blue, green, or pink (variation of brown) but occasionally you will get a brown layer. I have 4 EE's and they all give me a different shade of various greens and blues. Good luck!