New to survival hunter and wondering what the best spec (ie. Ferocity, Tenacity, or Cunning) is best for a pet in raid situations?

i looked through the forums and found the answer i was looking for but needed clarification on a detail that wasnt addressed and didnt want to necropost on that thread so started this thread to see if i could get a answer on this detail. my hunter is 32 i only have one pet but no slot for a second or third pet if eligible for a third pet slot. is there a NPC i need to find about getting those slots as i become eligible for them? if so, where can i find them? i have checked the hunter class trainers and they just go on about repec and glyph reset while stable master just wants to store pets. maybe i should just try to tame another pet with a current active pet to see if that opens up a slot or just replaces the current active pet. <----will try this while waiting for response. thanks in advance for any tips and heads up.