I’m sorry about your rooster. I bet he is a handsome fellow. Trim the feathers away from the wound as best as you can. Until your Vetericyn gets here you can rinse his wound with sterile saline solution once or twice a day and then pack with a triple antibiotic ointment such as neosporin. Make sure the neosporin has no pain relief in it. Keep the wound moist with ointment so it doesn’t dry out. It’s probably best to keep him inside away from flies until it can heal a bit. Treat him for shock very quickly after addressing the wound. Use 1 cup water with a teaspoon of sugar and a pinch of salt and baking soda. Gently dip his beak in to get him to drink some. You can also use Gatorade or some nutridrench mixed with water if you have any.