Anyone able to provide information on spawn conditions for bats witches?

Thanks!

Bats:

Light level: >8

Layer: >63

Witch:

Light level: I believe <8, however there isn't much information, that I can find, about this...

Layer: Probably all layers, but, again there isn't much information.

Another thing to note, they only spawn naturally in witch huts, which only spawn in swamp biomes, and very rarely other biomes.

Thanks for the info Leo, you are the MAN!!

Really?... I always thought Leo was more of a woman

Thanks.