Grill chicken thighs at 300-325F, skin side down for 1 hour.
Flip and remove skin - grill for 30 minutes. Flip back to skin removed side and grill another 30 minutes.Take off when deeply browned and internal temperature ~200F+. Rest chicken for 10 minutes, then shred meat.
Sauté diced onions and celery in neutral oil over medium heat for 3-4 minutes.
Add frozen vegetables, cook 5 more minutes.
Stir in chicken broth, milk, cream of chicken soup, shredded chicken, and dehydrated thyme.
Simmer 20 minutes until desired consistency.
Preheat oven to 400F.
Roll out pie crust and cut to fit soup bowls.
Fill bowls 3/4 full with soup mixture.
Cover with pie crust, crimp edges, cut vent hole.
Brush crust with egg wash.
Bake 30 minutes until crust is golden brown.
Cool 10-15 minutes before serving.