Maybe because she/he is maybe dying or if it's a girl it might be pregnant. My hamster, Ginger has swolen private parts. she might be pregnant because she was on top (or under) a boy/girl hamster. so just take time. if it doesn't heal within 1 month call an "excotic vet"
poop
Out of his butt.
none
Yes. Out their butt.
She's menstruating.
yes not sure what it is called but it means your hamster it going to die
No
Stick them in the same cage over night
if you have just cleaned it out it may have banged its nose or if you have to hamsters they may be trying to kill each other
Approximately 8.
It may be the male hamsters testies or if it is female it may be a tumor.
Poop sticks to bum hair because Your bum hair is very long obviously. Mine does not stick because i shave my butt