Hmm, thanks for emphasizing that we had strayed from the question of BEHAVIOR.
I don't know for a fact, but I feel if the chicks are raised in your coop and accustomed to your presence that they will consider that as home. I wouldn't recommend POL or older hens, though, as I recall one fellow getting some and only holding them in the coop for a couple of days. He proudly opened the pop door to let them free range and paraphrasing him he said "they just kept going and going and going...never saw'em again".
One thing to be concerned with is not so much a worry that your chickens might "stay" at your neighbors but that his contract might stipulate that he has to "remove" any non-contracted chickens....BIO-SECURITY *is* a major deal with the poultry industry. I know that around here there are warning signs stating "THIS IS A DISEASE FREE FACILITY" along with smaller wording.
Getting back on topic here... Poultry company employees are very adept and wringing a chickens neck. If a Tyson representative shows up and one of your chickens is pecking around him don't be surpised when he/she doesn't think anything of reaching down and popping it's neck and possibly writing your neighbor up for having it on the premises. So, for safety's sake I would teach them to be able to read TYSON on trucks, shirts, etc., and condition their behavior to flee for their lives at the sight of it.
Seriously, you might want to inquire with your neighbor about what TYSON's guidelines say about this. Around here the chickens in the commercial houses (broiler, layer, or breeder) belong to the poultry company and the farmer/grower is doing just that...growing them for the company and getting paid for the production...eggs produced, weight gained, etc., ...and the poultry company has the last "say so". Basically, if the growers facility for some reason doesn't come "up to snuff" with the company then the company can deny them chickens when the time comes. Ah, the warm fuzzy feeling of consolidated farming....
Best wishes,
Ed
