Unionville High School senior Mackenzie Hornibrook turned in a dominating performance at the PIAA District 1 swim meet, this week. PHILADELPHIA — Mackenzie Hornibrook, a senior at Unionville High School, turned in a dominating performance at the PIAA District 1 Championship Swim Meet on Thursday 2/29-Friday 3/1 at LaSalle University, winning the district champion title. Hornibrook, who is Captain...