For the turkey industry, this Thanksgiving is a guessing game.

Millions of Americans are expected to have scaled-down celebrations amid the pandemic, heeding official warnings against travel and large indoor gatherings. That leaves anxious turkey farmers and grocers scrambling to predict what people will want on their holiday tables.

Kroger — the nation's largest grocery chain — said its research shows 43% of shoppers plan to celebrate Thanksgiving only with those in their immediate household. It has purchased more turkeys than usual — in all sizes — but it's also predicting an increase in dem...