I believe in giving away to those who are neglected and starved. It's great to see people like you who like to have these giveaways but if my suggestion counts, I would suggest you to buy some pet food and feed the animals. I do the same for my street dogs and cats.
Animals are never selfish.
I see your point; but I live in a very small town and there are no strays lol, I feed my cat and dog if that counts for anything XD
Well, it's good that you have pets at home
You could have a contest then where you could ask users to answer few questions or choose a random number, write something creative, post an interesting picture or something that makes the winners deserving of your giveaways.