All diets are available as pellets and powder (or meal). Most can be formed into tablets (or "precision pellets"), and many can be made into concentrates for suspendable or nearly-soluble liquid diets.


We produce extruded pellets with as much as 60%kcal from fat (≈35% fat by weight); higher fats levels can be made into a convenient "cookie dough" consistency. Pellets are usually approximately 1.25 cm (1/2") in diameter by approximately 2cm to 2.5cm (.5" to 1") long; they are also available in smaller diameters (for instance 3/8" or 3/16" for ferrets, guinea pigs, and rabbits).

Reasons to Prefer a Pellet Form of Food over a Powder or Meal Form

  • Pellets can be fed in almost any feeder or hopper, or even without a hopper by simply tossing into the cage. Powder is fed in an open container on the floor of the cage or in special hoppers, either of which is prone to tipping and spilling, and to being soiled by urine and feces. Thus, the food source can be compromised and feeding can be interrupted.
  • With pellets there tends to be significantly less spillage and wastage of food, which saves both money and labor.
  • Pellets tend to be more "stable" than powders. Most of the ingredients (and any added test compound that may be added) are "trapped" inside the pellet, unexposed to air, moisture, and light; once mixed, the ingredients do not "settle out" or separate, and remain homogenously distributed. Powder, with its much great surface area, can have more exposure to the atmosphere and can spoil much sooner. They also can separate over time, with more dense components migrating to the bottom of the container and added test compounds sifting out of the diet.
  • Pellets can be "color-coded" with very small amounts of FD&C food colors to distinguish between different diets in a study. This not only increases the accuracy of your research by helping to prevent animals from being given the wrong diet; but it also increases the perception of accuracy of your data and the confidence you and others can have in that data when ultimately reported.
  • Pellets generate virtually no dust. Powders, however, are inhaled by animals (and by handlers), which can cause irritation and infection of the respiratory system.
  • By feeding pellets, rodent incisors can be worn down, whereas with powders rodent incisors may become overgrown.


Powder can be a useful form of diet if you prefer to add test compounds at your own facility rather than have TestDiet® incorporate those compounds and pellet the diet.


Our suspendable liquid diets are used in many types of research. They are convenient to use, mix easily, and, once mixed with water or ethanol, can be stored under refrigeration for several days.

Tablets ("Precision Pellets")

Diets can be compressed into tablets or "precision pellets" of precise weights and sizes for a variety of purposes, most notably used to reward and reinforce behavior through "pellet dispensers" (like "Skinner boxes") and to provide enrichment as treats. This "dosage" form is available in standard purified and grain-based formulas, and in formulas custom-designed for your specific research.