There is talk about some long ago family pets that have passed away but nothing dies currently in the book. Even the comments about past pets are innocent like, they had a dog named Clementine 20 years ago, etc. Nothing sensitive or hard to read.
The old family dog, Clementine, is seen by Margot at the end of chapter 36/beginning of chapter 37. It’s a graphic depiction of a decomposing dog but the dog is kind and gentle and not in any pain.