Can I play Flurry of Feathers during my beginning phase even if nothing triggered to chain off of?

No, you cannot play Flurry of Feathers during your Beginning Phase if there is nothing on the chain.

According to Rule 315 and RiftJudge FAQ #9066, there is no priority window to play spells before the Beginning Phase, and spells can only be played during an Open State (typically during your Main Phase) or in response to something on the chain (if the spell has the [Reaction] keyword).

Since Flurry of Feathers has the [Reaction] keyword, it can only be played in two scenarios:

1. During an Open State: During your Main Phase (formerly the Action Phase), when there is no chain.
2. In response to a chain: During a Closed State, when you are reacting to an item already on the chain.

During your Beginning Phase, if no other effects have triggered and placed items on the chain, the game state is not "Open" in the sense that allows for casting spells (as players do not have priority to cast spells during the Beginning Phase), and there is no chain for you to react to. Therefore, you cannot play Flurry of Feathers.