I remember reading that Sai Baba told one of his devotees to feed a black dog. Who was it and what chapter mentions this?

The provided text does not support the claim that Sai Baba instructed a devotee to feed a black dog. According to Chapter 0, it was a different saint named Janakidas Baba who advised a devotee named Kashiram to feed sugar to ants. This is why Kashiram was carrying a bundle of powdered sugar when he was attacked by robbers. The source material makes no mention of Sai Baba giving such an instruction, nor does it mention a black dog at all.