I first read a story about rats in Mary Danby's Nightmares 2 collection as a child. One of them, 'Heads and Tails' was particularly gruesome, considering the target group was children. In 'Rat Tales' the level of gruesome is handled well, from the entertaining but thought provoking Raticide to the comic sounding but unsettling Rats on the Radio. Some of the puns work well, Ratcula for example.
Even the hardest non-rat fan (and there's a lot of us out there) would find it difficult not to find one story here they might enjoy.