Animal behaviors are key signs of animals’ stress, disease, and overall well-being. This study was conducted in an experimental farrowing building using eighteen sow pens: nine exposed to natural heat stress under summer indoor temperatures and nine receiving cooling treatments via innovative cooling pads. Sow and piglet behaviors were recorded in an ethogram through direct visual observation every 5 min for 48 h. Passive infrared detectors were used for continuous pig behavior monitoring every sec. Zmodo wireless cameras were used for video monitoring to validate sensor detection results. Visual observation revealed distinct pig behaviors between the treatments. The sows had peak times in eating, standing, and drinking approximately from 05:00 to 12:00 and from 16:00 to 22:00. The sows under heat stress spent 49.3% more time lying (p < 0.01). They spent 10.7% less time sleeping (p < 0.05). Piglets under heat stress spent more time sleeping but less time nursing. The sensor outputs and pig moving behaviors (i.e., sow eating + standing + drinking + sitting + piglet walking) had a strong positive correlation (ρ = 0.81 for heat stress and ρ = 0.74 for cooling). In contrast, there were strong-to-moderate negative correlations (ρ = −0.77 for heat stress and ρ = −0.56 for cooling) between the sensor outputs and sow on-body behaviors (i.e., sow lying + nursing + sleeping). Video recordings validated the response and sensitivity of the sensors, with them able to quickly capture changes in pig behaviors and provide behavioral information about the nuanced pig movements.