You can use wood ash to pack the wound, or even flour. Anything powdery that sops up fluid. You can also use antibiotic ointment, which is gooey and will "plug the leak."
The yellow material sounds like pus, signs of infection. Get some triple-antibiotic ointment, or if you can't find that, then neosporin. Clean the wounds with an antibacterial soap or hand sanitizer, blot them dry gently with a clean, soft cloth or strong toilet tissue, and slather the antibiotic ointment all over the wounds.
Keep the wound area clean and treated until there are solid scabs.
If you can, put some poultry vitamin/electrolyte supplement in his water and keep him well nourished. and comfortable.