That looks like Skunk damage. Happened to me last fall, seems like you had/have a good amount of grubs. You might not be able to see grubs just yet as they're still hidden deep under for protection from the cold, the best thing you can do is wait until mid June to beginning of July to apply GrubEx from Scotts which is a grub preventer, or you can try a killer from Bayer which uses a chemical I believe was called "Sevin". Or you can do research on a long term prevention called "Milky Spore" but first check to see if they're grubs, skunks btw are nocturnal and only come out at night. If there food source is gone (grubs) chances are the skunk won't return anymore