From the PA Harness Racing Commission:
Standardbred horse owners must register their stallions and broodmares by the February deadlines for Pennsylvania programs that reward breeders who turn out top racers.
Stallions must be registered for the Sire Stakes Fund by Feb. 1. Broodmares but be registered “PA-resident” by Feb. 15 to ensure their foals are eligible for Breeders Fund awards.
Stallions must remain in Pennsylvania at a declared facility from Feb. 15-July 4 for their offspring to be considered eligible. Stallions used as racehorses must be approved by the commission and returned to their Pennsylvania facility after each out-of-state race.
Broodmares must live in Pennsylvania for at least 180 contiguous days, including foaling, and be in foal to a registered Pennsylvania stallion, for their offspring to be eligible for the award.