Pretty scarce. Having more than a full a clip for a gun means you're in good shape. 8-10 shotgun shells is locked and loaded in this game. You also don't want to use guns all the time because it's not too hard to get overwhelmed in this game. Especially against certain types of infected. Stealth is always your friend when applicable.Hows the ammo in the game? Scarce? Or enough to not worry about using guns? I guess since you get a bow, ammo probably won't be found very often.
Just be sure to use stealth kills and the bow when you can and it'll never be a problem. Enemies only take 1-2 bullets to drop anyway.