Turkey, Geese, Guinea as guardian animal?

[Mygooseandrooster]

I had African geese.

We have a White Chinese Goose, (as you can see in the pic), and he is a great guardian. Partly because he is white, so he can be seen better from the sky and look more intimidating(he is a guard against air predators) and also that's just how Chinese geese are. He is constantly checking the sky, and sometimes we see him hissing and flapping his wings and running at something in the sky. We also raised him with the chickens, so he attached himself to them and protects them. It seems to me, however, that African geese might not work as well since they are not as big, blend in better so they're not as seeable. It seems they might be reasonable guard geese though, they have close relations to the Chinese goose. How were your geese not working? Were they just not being alert, or not intimidating to hawks enough? (this is helping me as well, I am fairly new to the chicken field, and still learning about how to take care of my flock ) thanks