Regardless of whether you live on a farm or in a city or are "predisposed" to one opinion over another - it still isn't your right (or anyone's) to say whether or not chickens are pets in regard to chickens that do not belong to you. To do so would be presumptuous and rude, at best. If someone believes their chickens are their pets then they are their pets - it's as simple as that.
To clarify, I was speakin' of my own personal perspective on what was to be considered a pet and what was to be consider a farm product by our own family, and within the confines of our own fifty acre farm ... don't even recall it bein' spoken of, but that may be just the result of bein' taught very early.
As was the case w/ my nature to protect the other's right to have/express their own opinions (including your own ~'-)