Hearthpwn

Heroic Rend Blackhand
Ideally, you will want to set up Explosive Trap up by turn 3, use Unleash the Hounds in the same turn, and then Scavenging Hyena on turn 4.

Mulligan priority:
1. Explosive Trap or Mad Scientist
2. Unleash the Hounds

Bonus if you can mulligan for Scavenging Hyena

Your offensive strategy is to utilise  Unleash the Hounds to buff Scavenging Hyena.

If you're not drawing Explosive Trap or Mad Scientist within turn 2, concede and try again.

Heroic Razorgore
Mulligan priority:
1. Any 1-mana cost minion
2. Explosive Trap or Mad Scientist
3. Unleash the Hounds
Bonus if you can mulligan for Scavenging Hyena

Similarly, the strategy is to utilise Unleash the Hounds to buff Scavenging Hyena while also using hounds to keep eggs hp to a minimum.

Substitutes

If you find yourself missing some cards because you don't have it, I would recommend the following basic cards (sorted by priority):

Timber Wolf
Hunter's Mark
Arcane Shot
Houndmaster
Bloodfen Raptor
River Crocolisk

For Heroic Razorgore, Young Dragonhawk or any low-cost minion with windfury works wonders. 

Good Luck