The Human Society dont put pets down.
That's a great question! I think you should contact them directly, my opinion is that when they are older , they have a harder time being adopted out, plus I have noticed that there are many older dogs that have been there for a while now, you want to make sure where ever you take your pet, that they won't put him/her down if not adopted by a certain time frame, make a list of questions/concerns and call them up, it doesn't hurt to ask and stay confidential. Good Luck!
Thanks! Your answer is awaiting moderation.