Let's do the math. 1% chance of spawns at night for any individual wolf. Pre moder kill there where about 6 wolf spawns in 1 one 64x64 area(?). That gives a 5.8% chance that at least one of them is a 2* wolf. Meaning only after about 12 nights your chances go up to about 50%( 12 is the first integer n that makes 0.99^(6n) smaller than 0.5).

But that is just pre moder. With additional night spawns I'm afraid chances are even worse than that.