Hey guys! Here I am asking about animals again lol 

Mike and I are wanting to expand our zoo ever since we had a great Dane chow chow mix stay with us for a little bit. 

I've obviously been doing research into the dietary and exercise needs of a giant dog, but what I'm looking for some advice on is how to go forward.

Do we look at puppy breeders? Craigslist or fb marketplace for people who didn't realize how big they got? Rescues? Shelters? Everyone's thoughts would be greatly appreciated!

As a fellow gigantic pup lover:

If you go with a breeder that health tests, you are less likely to have a pup with wobbles.  Many people get big dogs and when they experience wobbles, give them up to shelters.

a breeder that health tests (hearing/heart/joints) 
you also need to look at what type you want, euro danes are much beefer . 
i actually know a few dane breeders but dont know how far you want to travel/your personal home base state? that is if your actually looking at danes :)

also understand giant breeds dont live long. 7-12 yrs and the 12 is really pushing it. 

if your going for a "pure" bred try to avoid fb market place/craigslist (chances are high they arent health testing)
if your looking for a specific breed hit up a fb search for groups. some are even specific for health testing