What will you use the homeless animals for? In my opinion, if you will treat the animals well and won't have issues with their original owners when/if they come to claim them then you probably should go ahead. And I think it'd be important to obtain permission from the community's authority as long as you are doing what is good.

In regards to investment/support from others, I think you may not need alot of money for the project if you could start small, rent a land (or check for free land you can use temporarily), start with few animals, and grow gradually (or expand with the income from the business). It's better to learn to run the business successfully before starting or you could start little and learn from there... so you don't make too much mistakes and lose the investment or lose alot of money