It’s it the first postThey are 8 months old. Way past the bony teenager stage.
Not necessarily.
Some of the larger heritage breeds are still growing past a year.
My Light Brahma rooster from the in-town flock wasn't fully developed until he was a good year-and-a-half or two years old.

Not poopy, just looks like she got wet/muddy at some point and her feathers dried up clumpy. You can't tell from looking at her, only if you flip her upside down. I flipped the rest of them and they all look clean and fluffy everywhere. This poor girl has a poopy butt AND a crunchy underside... I have a separate thread about her poopy butt where the majority opinion was to trim instead of bathe, but if she's crunchy on the underside in addition to poopy on the butt, does that tip the scales toward bath?