During the pro-day period of the off-season, NFL teams send representatives to different schools for another chance to evaluate and speak to prospects before the draft takes place. The Pro Days are a way for talent assessors to watch college football players go through various tests and demonstrate their skills by carrying out individual drills. As these exercises are usually held on their home campus, the student players are more likely to feel comfortable and perform their best.
Here is a short clip showing how the Bears spread out their staff in order to attend as many pro days as possible.