If you need more help with spawning duck feather, we have a detailed guide on our blog - click here to visit that page. Whenever you speak to a villager that says your name in dialogue (for example Gus at the Stardrop Saloon) you will be given the duck feather item. If you do wish to use this method, first set your character's name to when creating your save. A searchable Stardew Valley Item ID List, with all Stardew Valley cheats for the latest version (1.5) of the game on PC/Mac (Steam), XBOX One, PS4 and the Nintendo Switch. You can only set your character's name once, at the start of the game (when you create your world), for this reason we recommend you use the animal name method. You will then receive the duck feather item. To spawn this item using an animal's name, visit Marnie's Ranch, speak to Marnie and purchase an animal (we recommend a chicken as it is cheapest).
Spawning items in Stardew Valley is not done via commands, but rather through a cheat in which you must set your character's name, or the name of an animal, to the item code of the item you wish to spawn surrounded by.