| Poison will kill them but you might be sifting the insulation
for the body.
| They usually seek water and die there but not all of them. It
only takes one
| dead rat to make you swear off poison in the house. You will
live with it for a
| couple months.
Actually, unless you foolishly put out nearby water for them, as
one poster suggested, they will leave the attic to find water.
By the time they find water, the poison will act pretty quickly
and they won't be able to climb back in, but ... if they have
access to the basement or cellar, you might find them down there.
As a general rule, a dead mouse in a thick pile of insulation
won't cause a problem unless you are finicky and will be pulling
up the insulation for some other reason. Depending on how easy
it is to get back in though, some MIGHT make it back. If one
dies laying on the ceiling material, plaster or plasterboard
could eventually allow a soak-thru over time, marking the
ceiling, but as long as your vapor barrier is in place and
properly installed, no problem.
We just put a box of poison near wherever we know they are.
It disappears quickly if there are more than a couple, so when
empty, replace it. At first we used two boxes at a time, but
since then one lasts the entire winter and seldom has anything
eaten from it. That's because I searched out and sealed up all
the accesses with Silicone caulk or aluminum. Well, except one;
gonna need a clairvoyant to find that one I guess! Every fall a
small amount of the poison gets eaten.
We live in the wilds; about any kind of mouse, squirrel,
chipmunk and other vermin you can think of will get into a house
here if you aren't closed up. It's God's country. PETA? Not
worth the effort to comment further on such fanatics. They'd
rather see an animal die naturally from its injuries, sickness,
or old age, in the cold freezing temperatures of winter. No use