You can go with beer traps, snail bait (iron phosphate or metaldehyde), Muscovy ducks, or copper strips. I haven't tried ducks, but I've had the most success with a metaldehyde liquid formulation. The most popular brandname is Deadline, but there are less expensive generics that are as good. The liquid is good for a long time whereas the pellet and powder tend to absorb moisture out of the air and become ineffective and messy after a number of months.
Get a couple sticks, apply a line of about an inch, and lie the sticks down, away from the window, preferably in the shade and where the sprinklers or watering won't hit it. Repeat every 2 or 3 weeks until the slugs disappear.
Check out the snail and slug management document from UC Davis at the link below.
I'm in the ground floor bedroom, (what I imagine should be a sitting room or something like it) slugs have been getting in. I kill 'em when I see them with salt and I've put slug pellets outside front and back of the house. They don't bother me particularly because they aren't near the bed, but I don't need pets which might attract happy go lucky spiders.
I can see there are slugs living on the outside of my window underneath the bit which would open up. But I really can't believe they could be squeezing through the window opening when completely shut. They started to move in sometime February.
