They're likely Easter Eggers which are often called Ameraucanas. Ameraucanas are a purebreed and Easter Eggers are hatchery chickens- both lay blue eggs (Easter Eggers lay green and tan as well). They're great birds to have around- I've had many. Easter Eggers are typically lay well, aren't flighty or aggressive and seem to like human company. Have fun with them!
Per APA standards, an “Ameraucana” will have slate colored legs. These do not, so an easy check for that breed. EE often have green or “willow” legs. Sometimes these birds are marketed as “Americana” note the “I” rather than “au” in the spelling. Misleading? Yes.