Once a snake is safely head tubed, food may be introduced in the form of a slurry delivered through a tube, or in the form of whole dead prey as shown here. Care must be taken not to accidentally introduce food or medication into the snake's glottis (windpipe).
Keep in mind that if you have a weak, debilitated animal on your hands there is a good chance that peristalsis is weak or absent - in other words, its GI tract won't be working and it will not be able to digest any food that you put down there. Start with a small quantity of a dilute nutritional slurry and make sure that what goes in also comes out. If you put a lot of food down a snake that isn't being digested, this can result in serious bacterial problems as the food will simply rot. Whole prey should only be given to relatively healthy patients with functional GI tracts.
Some good nutritional slurries include Mazuri Carnivorous Reptile Gel, Walkabout Farms enteral diets and Hillspet A/D prescription diet. Mazuri is more nutritionally complete for reptiles than Hillspet, but the regular slurry can be gritty and requires the use of a larger bore tube to prevent sticking and potentially harmful pressure backups when used for smaller snakes. Fortunately Mazuri's veterinary nutritionist is very understanding about formulating diets for customized needs, so if you do a lot of assist feeding it would be worthwhile to contact them directly. Any zoo diet formulated specifically for carnivorous reptiles such as Mazuri is a much more nutritionally complete and healthier product for reptiles than compromises involving dog or cat food, baby food, etc. Additionally, A/D should not be used on reptile patients with possibly compromised kidney function or patients on nephrotoxic drugs such as aminoglycosides (Amikacin) due to its high purine content. Purine degrades to uric acid, putting an additional burden on the animal's kidneys.
A very debilitated animal should get a thin, syrupy slurry of Pedialyte (or any electrolyte solution) with a small amount of dissolved nutritional concentrate such as Jump Start or Nutrical. 10cc's per kilo is a good starting amount for such a patient.
To deliver a slurry, choose a syringe of no more than twice the volume of a normal, comfortable prey item for the snake. Ie, the liquidized remains of two pinkies, two fuzzies, two adult mice, etc, should just fit into the syringe with little room to spare. You do not actually have to send any mice through your Cuisinart, though this is a perfectly fine feeding formula if you have a high quality lab blender. Use the mouse estimate to choose a syringe that will not cause injury to your snake. Cut a length of clear aquarium tubing to fit on the end of the syringe, or use a red rubber urinary catheter as pictured in the photo below. A catheter tube can be cut to fit tightly to the end of a standard plastic syringe. If you are using aquarium tubing, use heat to smooth and round off the ends to avoid injury to the snake.
Introduce the tube into the snake's mouth using forceps. An introduction from the side may be easier and may help you avoid the glottis, and you may wish to wet or lubricate the tube with KY jelly first. Caution: if you accidentally deliver medication or food down the glottis, this is likely to kill the animal. Push the tube down the snake's throat gently once you have determined it is not in the glottis. Begin delivering food or medication once the tube reaches down 20% to 25% of the snake's length.
When assist feeding whole prey items, use forceps to place the mouse's head in the tubed snake's mouth as shown above. Manipulate the mouse about halfway inside with the forceps, and then switch to a "plunger" to push it down into the throat to avoid injury to the snake as it may bite down on the forceps. Your plunger can be any sort of smooth stick that is clean and not prone to cause injury or catch teeth if the snake bites down on it. The end of a hard plastic spatula works well, as does the handle of a Midwest or Furmont mini-hook.
Once the whole prey item is down the throat, you may choose to continue pushing it down with the plunger, or you may "milk" it down the snake by squeezing your fingers gently on the outside of the snake as if you were milking a cow. I find the external squeezing method to be less likely to cause harm to the animal, as there is some danger that a snake may struggle with the rigid instrument inside of it. You may want to back the snake out of the tube at some point during the feeding, but this will depend on the species and the situation.
Read another article on tube feeding a snake,
written by a Snake Getters volunteer.