They sell Gordons or Martins permethrin 10 concentrate to make a solution to use in a spray bottle 1 1/4 ounce (37 ml) per Gallon or 9 ml per quart. They have permethrin garden dust as well to use in cold weather. It is safe for mites and lice in poultry.
Temporarily you can use a length of aquarium air tubing (found in pet aisle at WalMart) which can connect to a 35 ml regular syringe from a feed store. A vet can sell you a feeding tube and a catheter tipped 60 ml syringe which is a larger bore tube. The air tubing will pass raw egg, plain yogurt and very thin foods plus water.
Sorry that you had trouble finding the products I recommended yesterday. I thought that I had given enough info, but glad you got everything, or will soon.