Also, try to go either early in the morning, or later in the day when the wolves are more likely to be more active and vocal. The mid-day or when it's warmer usually find the wolves hidden or resting.

Oh man! I just saw this question. Obviously way too late, but yes, it's all behind a fence and you have to be lucky to catch the sight of a wolf actually. They told us they keep them 'not used' to people, because they want to preserve their wild nature, so, yes, I guess you can be unlucky enough and barely see a wolf. For my kids it was a mix of disappointment that there was no closer encounter with them and, yet, they still loved the visit and my son still talks about it. Anyway, You've already come and gone probably. So I hope you weren't disappointed if you decided to go.

You have to book in advance.

I bought a year membership with a groupon. I think general admission is $20 and very well worth it!