I have a hooded siskin and zebra finch together in a good size cage they've been together for months no problem sleeping side by side, eating together, even bathing together but this morning my hooded siskin hen has started to pull out his feathers, he is a rescue and one of his legs doesn't function so anything that happens to him I freak

I don't know if she's bullying him or bored I just don't know, I'm keeping her free-flying in my room since it's the second time today I've caught her doing it.
Please help
