A trainer, owner, or authorized agent may not enter and start more than two horses of the same or separate ownership in a purse race or overnight event, except under the following conditions:

(1) Stake races;

(2) Races in which there are fees required to nominate or enter; and

(3) Allowance/optional claiming or maiden special weight races. In these races a trainer may not enter more than three horses. The third entry may not exclude a single entry, or be allowed if there are less than seven entries received prior to the entry of the trainer's third horse.