Mulligans
This is a mid-range attrition hunter. The main problem Hunter had while playing mid-range/control was its hero power as it had no control on the board. Now with Dinomancy you not only get board control but you retain the option of dealing 2 damage to the face(and hopefully repetitively).
Play your 1 drops on turn 1 if you can. If you topdeck them later then save it for Stampede. You want to have some cheap beasts for stampede.
There are 6 Deathrattle minions to synergise with Terror Scale stalker but don’t hesitate to play it with activating its effect. Always keep in mind that you will have a lot of resources to play with because of stampede so don’t save up cards. Just save 1 drops for stampede.
Even though this is a midrange deck, this deck is very good at pressuring your opponent with cards like Bittertide Hydra, Knuckles and the hero power.
Replacement:
Knuckles: Replace it with Starving Buzzard if you need card draw or replace it with another Tundra Rhino or Volcanosaur.
Rat Pack: Replace it with Infested Wolf. Infested Wolf also makes your curve better but rack pack is just powerful, especially with the changed hero power.
Call Of The Wild: Replace it with Volcanosaur. You are getting it for free!