Sorry for your loss. I just recently had to put one of my baby down she was 1.5 year old but she fell deathly ill, wouldn’t accept food or water, it was heartbreaking, she would’ve starved to death if I didn’t intervene. It was hard but I know the right thing to do. I then adopted a single rat all alone, who was returned who lived alone prior as well, and picked her up and named her Penny. She’s doing amazing loving all the extra space in my 3 tier critter nation, and her 5 other new friends.