Pokémon Sword and Shield have some eye-raising methods to evolving Pokémon in the Galar region, but none of them quite compare to Galarian Farfetch’d and Sirfetch’d.
The small duck Pokémon has a questionable method to evolve into its next stage, Sirfetch’d, as long as certain criteria are met.
Evolving a Galarian Farfetch’d into a Sirfetch’d is tricky. You’ll need to have your Galarian Farfetch’d deal three critical hits in one battle.
That means you’ll ideally need to put him up against a gym leader or a trainer with three or more Pokémon to increase your chances of dealing three crits. It doesn’t matter what level your Galar Farfetch’d is—as long as you meet the criteria, it’ll evolve after the battle ends.
Just remember, this has to happen in the same battle. Landing three critical hits in three separate battles won’t be enough for Galarian Farfetch’d to evolve. The best way to get critical hits will be a mixture of Focus Energy and Dire Hits to increase your chances of a crit.
Then you can go about your journey with your new Sirfetch’d or throw it into your Box and start working on evolving your next Pokémon.