Slugs are not the best for hogs, they will eat them though if they are starving. Cat or dog food is great, definitely no mealworms or bird seed as they make them really sick.
You are very lucky to have these endangered sweethearts in your garden. If you can put out fresh water and cat / dog food every night (dry kitten biscuits is best, or anything that lists meat first as that means the highest ingredient is protein) you will literally be a life saver.