There appears to be a Machlokes between the Kollel's Background to the Daf and their Questions and Answer to the Daf on Shabbos 19a.
Q&A says 1c) asks May one feed an animal that is not one's own on Shabbos? and answers "No! It is forbidden to feed an animal that is not one's own on Shabbos"
Background to the Daf (line 3) says "...even if the dog does not belong to him, or is ownerless, it is a Mitzvah to feed dogs since they are always hungry (MAGEN AVROHOM ORACH CHAYIM 324:7) "
Trei Amoraee Aleebah d'Kollel? :-) Keep up the great work!
Thank you very much for pointing out our oversight. It seems that the Machlokes within the Kollel is actually a much older Machlokes, as the MACH'TZIS HA'SHEKEL (OC 324, on the Magen Avraham there, #7) points out. The Machlokes, though, applies only to dogs. For other animals, though, what was written in the Q&A section is correct.