What exaggeration had Grandpa told the other hunters in Chapter 15?

Grandpa told the other hunters that Billy's dogs treed six coons in one night.... three in one tree.

Grandpa was hopping around like a grasshopper, going here and there. Once, passing a tent, I heard his voice. I knew he was bragging about my dogs. I smiled to myself.
Another hunter stopped me and asked, “Is it true that your hounds have treed six coons in one night, three up in one tree, or is that old man just blowing off steam?”