Hello everyone I kinda new to raising chickens my first flock is seventeen weeks old now and that about how much experience i have. I ordered 26 RIRs from mcmurry hatchery when i ordered them I had the understanding that they would be pure bred rhode island reds. but i have been told that hatchery chicks are not pure bred and that they would not grow near as big as what a pure bred breed should. Is this true? How do I know if my breed is pure? and also long does it take for a RIR to be full grown? the hatchery said my RIRs would get 6 to 8 pounds but they are no where near that and they are 17 weeks old.