Visit the farm and get to know the farmer and his and her practices with his/her flocks and all the animals. You will know if they are well treated and properly cared for by the way they are housed and taken care of.
We are a 2 person, small farm, full time farmers and we take great care of our animals and give them much love and attention. I often say we have one "natural" born child and 400+ others. The 400+ eat better and more often than we do with our farm schedule. I do advertise on Craigslist and am a member here obviously but am a fulltime farmer.
If the farmer doesn't want to show you his/her farm, I'd drive off and NOT buy. I have bought off craigslist from a NON farm and will never do that again. The chickens were ill and all died within 4 days of purchase and I spent $60 for 6 hens and a rooster and lost all of that but moreover was so saddened and suffered alongside the hens and rooster and spent many long hours trying to save them - to no avail. Luckily they were in isolation which I do with all my new additions. When I contacted the original owners, they wouldn't even answer my calls! I guess they didn't care. I wrote an e mail explaining I just wanted them to be alert to possible problems with their flock. Again no answer.....A real lack of caring there.
I also like to share with the buyer how to care for the chicks. It's part of my connection to the little babies and I do care for them.
I have bought from hatcheries to have the heartach of opening boxes of half dead chickens and waiting for additional chickens that were sent a month later. This was shipping error but still so sad to see. Hope this was helpful to your thought process. Come by and buy some chicks. We currently have white leghorns and rirs and are round the clock hatching as we just love our christmas present - a used wooden cabinet incubator!