This is how I handled it with my family this past October. I have 2 kids...7 and 3 at the time it happened. I was as honest with my children as I could be, given their ages. I told them on a Tuesday night, and we planned a special family night with our dog on Thursday night before she was euthanized on Friday. We made some steaks on the grill and allowed the dog to eat with us at dinner, we allowed the kids to pick something (e.g., toy, blanket, treat) for her to be buried with, and we all snuggled in with her on the couch and watched a movie (she normally wasn't allowed on the couch). It allowed my children to have some closure without having to experience all the gory details. Went as well as it could have gone.