as in chicks, are a good variety imho and not dangerous. Larger birds that could be a danger, I see no need for. The only cases I've seen them fed were by people just doing it to make and broadcast a "let's see what the snake can eat".. video.
I see nothing wrong with variety?
And talking morelia in my case, but have thought about doing it in the spring for my JCP girl that's a pain about thinking rats are as edible as DIRT and only taking mice when she needs something much larger than the biggest mouse.