That doesn't justify making unevidenced claims such as "rats know when they are going to die and that makes them suffer", "searching for food is entertainment value for rats", "killing a rat that has 'bonded' with another causes suffering", and so on.
Humans exploit other species to preserve or better our own. That's not exactly a world removed from any other 'natural' interaction between species. Why don't you go and complain to the rats about the suffering they cause?