Why do bats huddle during late fall?
This is basically a trick question and a bit of a cheap shot. All of the reasons cited boil down to "bats huddle to conserve heat", they are basically the same, single, reason.

In order for bats to feed, they need to move, fly out of their cave or wherever they happen to sleep and go forth and look for food. Therefore, they will not be able to huddle while feeding because they will be flying around trying to find fruit or donkeys or whatever each species feeds on. Unless they can figure out a way to huddle while flying, they will not be able to huddle while feeding and so number 5 is wrong.