There are animals people have deep affection for and you’ll find great resistance to these experiments, never the less, I think you can get valid data from experimenting on “lower” animals.
The whole point of using a thought experiment is to gain intuitions about the "but what if it wasn't a person, but a chicken instead? Would that be equivalent? Why?" Ie, the value of the experiment is in the experiential learning of the attempt to arrive at the answer. At least, imho
Sure, you can do things that you consider evil just to see how you would really react to being presented with such an unpleasant binary choice, but if you chose to do it, was it in fact not evil to you, are you just pathological, or are you perhaps in toddlerhood, where you don't yet really have an intuition for your own relationship with causality, such as it is?
