During the landing roll on an airport at dusk, 3 or 4 deer ran out across the runway traveling right to left. The airplane collided with two of the deer and the engine lost power as one of the propellers struck a deer. Substantial damage was sustained to the engine mount, firewall, and right forward fuselage. The flight instructor reported there were no preimpact mechanical malfunctions or failures with the airframe or the engine that would have precluded normal operation. The Federal Aviation Administration (FAA) Airport Directory information for the airport listed a warning for deer on and in the vicinity of the airport. A review of the NTSB accident database and FAA wildlife strike database did not locate other incidents of wildlife strikes at this airport. The flight instructor further reported that the accident could have been prevented if deer fencing was installed at the airport.