vs orc I wall off my base so the BM can't kill whisps and go hunts build again, making sure part of the wall is an AoW so you can move it if you need. Go to 20 food with whisps/dh (lumber is for fast tech) que up a hunt and tech asap, make 3 hunts total. Second my DH comes out I am harasing the BMs creep or killing burrows (if he tries to attack your base he wont be able to do anything). I put pressure on the orc the entire beginning of the game. Once you hit tier 2 get a beast master or a keeper if you think the game is going to last longer (keeper is 10x better to kill kodos) and put up dual lores and go to t3 as soon as you have gold for it (should be fast). The second you hit t2 with DH + 3 hunts and you get a beast master you have a huge advantage over the orc. Start summoning up quill beasts and go to the orc base, Focus burrows or kill beastiery/spirit lounge if they are still being built. Once the shadow hunter comes out you should leave unless you have a staff with you. Power creep with rejuv until you have master bears. If you still have hunts let them die to creeps so you can stay under 50 food and keep pumping bears/dryads.
Once you have like 4 master bears you can hit orc again and expand while he is defending his base. He will have walkers/kodos to counter bears in which case keeper is a little better, if he has wyverns then you can just put an orb on the DH.
#1 thing vs orc is the tier 2 push, you can set him back really far by killing burrows/production buildings and he wont have time to counter bears. Most pros use the mass talons strat with DH/BM/tinker but I like bears way better. You can check all your statistics on the ladder website, my win % vs orc is way higher than any other race.
You can get good kills on the BM with roots+mana burn + bears focus, especially if he is over aggressive with it. Even if you don't get a kill he will be a lot more hesitant if he sees you focusing with roots+bears.
I used to have a shitload of orc reps but they are all from last patch so u cant watch them. but that is my orc strat.