The pig farm must have sounded very promising. The house appears to have been the main target of the search.
A pig farmer said seven [out of 15] FBI investigators arrived at his home last Friday and asked to search it without a warrant. They were there for nearly two hours, taking photos of the interior of the home and also searching his garage. He said investigators then asked to interview him off the property and kept his cell phone overnight to check his records. The farmer has not been charged with a crime and said he “has nothing to hide.”
http://www.foxnews.com/us/2018/08/01/mollie-tibbets-disappearance-total-shock-iowa-residents-say.html
This was the first lead, that we’re aware of, that appeared to have ignited some real interest. We’re yet to hear further about the truck stop where someone saw a person resembling Mollie.