Dsc love animals and we have several pets. Their mum doesn't like animals but buys them as a tie to make dsc want to stay home with 'oh your poor puppy was whining the whole time you were gone because he missed you so much' 
In the past three years they've been bought rabbits each Easter, all of whom have 'dug out and escaped' within a month. They've had a puppy each Christmas, one who got accused of biting dsc mum so had to go, one who chewed a shoe so had to go and the third 'ran away.' they've also had 5 cats, all of whom have 'run away.' Dh says exW used to hate cats so much she'd use non pet friendly weed killer in their garden and aim for them with the car if they were in the road 
I think it's all emotionally damaging for the children and that theres a possibility she could be hurting the pets, or is extremely incompetent at the very least. Aibu to not just stand by and want to do something?