Many parks have policies that state "no farm animals". Might even be required by local health or zoning laws. I know of a park that had a problem with a pig. The pig parents set up a pen and the pig decided it was a good place to root. The park lost a tree and had big hole where there was once grass. I know the story because the park called and warned that they were headed towards my part of the country (contrary to popular belief, parks actually do work together on some things). They didn't try to stay with us, so that was the end of the tale for us. But it goes to show the adage "why take chances" is usually a sound business practice.