All you need is an apple (could also use a potato), some toothpicks, mini marshmallows and food coloring.
Start by separating the marshmallows into individual bowls. Add food coloring to the bowls and stir. I found the gel food coloring works best. Give your marshmallows 1-2 hours to dry on a paper towel before letting your little one handle them or it can get very messy :)
While the marshmallows are drying, insert toothpicks in the apples on one side. These will be the base for your turkey feathers.
Once the apples are ready, let the kids go to work. Smaller fingers might need a little help getting the marshmallows on the toothpicks. You could challenge older kids to make a pattern with their marshmallows.