A:Answer Depending on the shape of the turkey, the lower oven for the LG 6.9 cu. ft. Smart Gas Double Oven Slide-in Range with InstaView®, ProBake® Convection, Air Fry, and Air Sous Vide, Model # LTGL6937D will accommodate up to a 22 lbs turkey, but as you are aware from your own experience, not all 21 lbs turkeys have the same shape. The interior W x H x D dimensions for the lower oven are 24 13/16" x 14 1/4" x 19 15/16" so you can measure your 21 lbs turkey to make sure it will fit...^Ivan