Craigslist can have ads from very good breeders, and like you said, others off loading old or ill fowl.
Arming yourself with knowledge is a big help, but even then, make sure you quarranteen all new entries to your group flock.
Make sure that most all of your birds are immunized for diseases in your area !
I like McMurry...if what you want is a start, and breakfast, go to them for a start and education.
What I do not care for is "hatcheries" which are justbasically getting rid of birds leftover from hatches in other big hatcheries, they are called "Clearing Houses" and if you order a few different breeds in your order, you may get "chicks" in a vast spread of age...new babies, and maybe some as old as 3 weeks....and imagine what they have been through going from their hatch, to trucked to a different place & then resold & shipped to you.
I am not sure which are clearing Houses.
I know Duane Urch, Glen Drowns, and mcMurry, all hatch and there fore save (and pay attention to) their breeding stock...year by year.
There maybe more, I just don't go there anylonger.
If I want something, I put a line out to the SPPA, ask about the old breeders, and go from there.
BUT
My main favorite, that I have bought year after year (25 to 50 a year) have been McMurry's Plymouth Barred Rocks..............
Living up on top of Aneas Valley (years ago) FREEZING....I put a mail order in (with a money order back then) for 50 Barred Plymouth Rocks , of which 7 were males...and the date was to be April first...but the Post Master called on March firest & said my birds were there & apparently I marked the wrong box !
Not having any heater in my Ford pick up, I drove to Okanogan & picked the boxes up, and made my kids bundle the babies up...we got home and opened the OVEN, added a rabbit cage on the oven lid, and put the babies in it, and turned on the gas.
Gas oven.
They did fantastic !
They were fat, healthy, lively despite the snow still on the groun..they were an extremely healthy stock.
The pullets laid right on time ...at 6 mo, and they were friendly, but predator wise.
The first batch of McMurry barred plymouth rocks I bought were in 1972...loved them then... and bought them and other breeds repeatedly from their hatchery.
Long story, but funny, no ?
I have lived up in the deepest woods of Elmira Idaho, to the Sierras of california, to Okanogan, WA.
I miss the sage from E WA, and the open plains
And the Quaking aspen in North Idaho (and Moose on the porch after the chicken food!) Suddenly Western Wa seems boring..............and snowlesssss....