Here's the thing - realistically, you have no say over what happens to those birds once they leave your possession. You can put all the stipulations you want in an ad, but once they're gone, they're no longer yours. The only way to really know how they're being treated is for you to build them a bachelor coop and keep them yourself. Personally, we eat our extras. I know that's not a option for everyone, but after putting several months worth of time and feed in them, I'm not giving them away - my time and money are worth more than that. Also, I know that my chickens are treated and fed well if I keep them. I believe they lead reasonably happy chicken lives up until that one bad day where their last few seconds may be a little stressful.
Something to think about in the future. You might want to get sexed pullets next time, or even older ones to be sure you know what you're getting.
Something to think about in the future. You might want to get sexed pullets next time, or even older ones to be sure you know what you're getting.