Good question.. I've been wondering that too. I think it depends on the breed too though. I know that Jersey Giants aren't fully grown until two years of age! (And I have two of them )
It depends on the lines and the breed. Larger breeds, such as Brahmas from hatchery lines can be full-grown and productive around 8 months of age. Leghorns from production lines could lay as early as 16 weeks. Brahmas in show lines could take more than 2 years to fully develop, Langshans are similar, they just don't look "finished". It all depends on what you have.
Thank u that's wat I thought . I have br, rir,Delaware and my btm and STd araucanas . A women came to buy birds after she seen my cl add . I was selling my STD clean faced tailed araucanas as Easter eggers . Any way she said chickenscshould be full grown by 3-4 months snd that all my birds I was selling were all btms. Becuase suposably at 3-4 months old her birds were full grown . And that there rooster is the size of my blue slate Tom turkey !!? Now yes even STD araucana aren't as big as Easter eggers . rir, and br, etc but the STD araucana are the same size now at 3-4 months as my br and rir. I hate it wen ppl who have no clue what there doing try to tell you ( the person who does know ) that there wrong . Seems to happen alot in this hobby ?
next time just tell them that's the difference between hatchery stock and better stock. yours may take longer to grow up but in the end, yours will be bigger then the hatchery birds (if this is true)
