You would not have to show me a research study to teach me that animals feel empathy for each other and for their young. I found your link extremely interesting! Thank you for sharing that.
But I have observed things like cats nursing baby rabbits, dogs nursing things such as lions and my own pets "caring" for each others wounds. One of our own dogs "mothers" everything here and has empathy for PEOPLE here when they are sad. I also know of some dogs that have been taught to warn people of impending epileptic seizure. If they were not using the quality of empathy in a dog, how on earth would you get a dog to care about this?
Of course chickens feel empathy. And isn't the term "mother hen" the way to described an overly doting mother?
What surprised me is that researchers are trying to put a quantative value and study something as basic as empathy. It is like trying to measure something like "love.:
But if you find somewhere that someone is trying to measure THAT, I'd be interested in the link! Interesting reading and topic.