glitzhome20.67" L Birdhouse for Outside Rustic Wood Barn Design Extra-Large Hand Painted Bird Houses

Does the metal roof make it too hot for birds? Do birds actually use it? It's a shame that it's such a large space for one bird, should be divided.

Is this suitable or large enough to use as a squirrel house?

How does this birdhouse hold up to the weather, should I varnish it?

Can the birdhouse be hung on a hook?