Answer:
You CAN substitute Poultry Seasoning for Thyme, if you are not a fan of Thyme, and do like the flavor of Poultry Seasoning; however, if you are substituting it because you do not have Thyme, it is not going to have the same effect. Poultry Seasoning contains: Sage, Rosemary, Parsley, Marjoram, Salt, Pepper, and Onion Powder. If you DO substitute it, keep in mind that your recipe is calling for a specific measurement of Thyme, and it would not take as much of the Poultry Seasoning in the recipe. Also, you will need to account for the extra salt, if the recipe calls for salt, make sure you don't add quite as much as it calls for, since the Poultry Seasoning will add more salt to the recipe.