Dogs will become depressed when another dog goes. So if possible I like for my remaining dogs to see and sniff the one if possible. I have had a few dogs put to sleep here at home, and 2 have passed on their own unexpectedly. My oldest dog lost her whole pack that she had grown up with, she was the youngest at one time. It took her a few years to come out of her funk, probably just as long as it took me. She was very bonded to my last boxer, and so was I.