The most common way sees a pop-up automatically appearing when you login to the game. You'll be thanked for your participating in Lighthouse Cove and will be told you can find your new cow in your Gift Box. If that doesn't happen, however, you'll want to keep a special eye on your email, as the developer is sending on newsletters to players containing an "Accept Gift" link that will let you claim the cow manually if you don't receive the pop-up.
Either way, we're specifically told that this release deals with Farmer Appreciation Week, so it's possible that you'll only be able to claim your cow for a few days more. Make sure you login to your farm sooner, rather than later, to have the best chance at securing one of these cows for yourself. One last thing: if you've already received the Skeleton Cow in-game automatically, you can't click on the email link to claim a second (trust me, I tried).
Check out the rest of our Halloween coverage right here.
Did you receive a Skeleton Cow in your FarmVille farm this morning, or have you yet to even receive an email about the prize? Sound off in the comments.