... that there will be (or even should be!) other animals added to HP? (e.g. cats, farm animals, wild animals, etc.)

No. It's called HORSE Phenomena for a reason. It's enough having the canine species around.

Nope. There was a discussion about that in the past, and Sam assured us there wouldn't be anything like that added. Sam used to have a game called Animal Phenomena, where people could breed felines, horses and dogs (I think there was something else, too), but I think it was closed so Sam could focus on HP (not 100% sure about that).

I am going to say no too, but I would love to see Animal Phenomena open again soon!

I like to see ap open again..

concourse has mail on hp and fb

Animal Phenomena might open back up one day but I think right now Sam is trying to focus on HP for the moment! I wouldn't expect AP to be  back up super soon, but I also have my fingers crossed for a one day re-opening date! :) 

amen to that comment siib because id kill you all in cat breeds xD

That’s what you think, phiz 😏

Just as an official answer, no that’s not in the plans. I think more species deviates from the nature of HP and would change the game too drastically.