Any time you add a single ingredient in addition to a complete feed you will alter the nutrient intake of the bird which may affect the productivity.
To illustrate consider making a cake using a Betty Crocker mix. Everything you need is in the box, except for eggs and milk, follow the directions and you get an acceptable cake.
Now consider changing the mixture by adding more flour "because I got a good deal on it". The resulting cake won't be acceptable.
The same principle applies to adding to a complete commercial diet.
Jim
To illustrate consider making a cake using a Betty Crocker mix. Everything you need is in the box, except for eggs and milk, follow the directions and you get an acceptable cake.
Now consider changing the mixture by adding more flour "because I got a good deal on it". The resulting cake won't be acceptable.
The same principle applies to adding to a complete commercial diet.
Jim