Did the rats fool the doctor and the men in the truck?

The seven rats made themselves seem to be an entire pack, and yes, the succeeded.

Then, as if by agreement, they stopped waiting. They ran. All seven of them, not back into the woods to safety, but out of the woods, toward the stubble of the rosebush, toward the men. At the edge of the bush, they stopped as if in confusion, ran to the left, ran to the right, then fled back into the woods again. Now they were out of sight of the men, but not of Mrs. Frisby. Instantly they regrouped behind the blackberry bramble and charged out again—but this time in smaller numbers: first two, then three, then two again. She saw what they were up to. They were not in the least confused; they were making seven rats look like twenty rats, or forty, a steady stream of them.