I made a thread for people once they get their letters sent out, so that we can see how many people we have doing this:
https://www.backyardchickens.com/forum/viewtopic.php?pid=1840163#p1840163
I think a handwritten letter would show a more personal aspect, if you have the extra time to do this, I think it would help alot. I plan on writing a letter, Maybe if enough of us do this, they would think about putting some chickens out on that lawn.