We planted 5 trees and we had one that turned brown and died. We planted another in the same spot and the second one has dried up also. We live in the country and have a lot of shale. We planted like 3 or 4 feet apart and the fourth from left has died and others are doing great. What could bethe problem.

Texas is a long way away from Illinois, but transplant shock is most likely the problem. Arborvitae have become a landscape staple in much of the country. If the soil was the issue, plants only 3-4 feet away would be impacted as well. If you are going to replace this again, wait until a proper time for your part of Texas. Pay close attention to watering and monitor at the base of the plant, that will be where the roots are and where the water will be needed. if you can provide some temporary shade and wind protection, that will be less stressful while the plant recovers.