Higher digestibility and slightly higher energy values are the trends in producing a very economical diet with excellent health maintenance. This process is more commonly used by farmers to produce low cost chicken and pig feed. Extrusion processing uses higher moisture cooking and is more commonly used for human and pet foods. There is no doubt that most extruded foods are more palatable than the same formula pelleted. Also pellets have a tendency to produce a fine powder when the bird bites into them leading to wastage.
Extruded kibble tends to break into still edible pieces rather than explode into a powder.
The quality of protein, that is its amino acid balance and digestibility, is as important as the total level of protein in a diet. So besides the obvious palatability advantages of this mixture of ingredients, benefits to protein quality also occur. The different amino acid profiles of these various protein sources complement each other, resulting in a premium protein of high biological value. This is very similar to the Broiler poultry requirements, which we could then use as a starting point for estimating parrot growth requirements. Feather protein contains a higher level of cystine and thus during maximum feather growth in a nestling or molting in an adult, the relative requirement for cystine increases.