Here is the email I received from the company when I inquired about it:
"Thank you for taking your time to contact BLUE.
Because BLUE is so rich in nutrients, we recommend 3-4 weeks of transitioning. This allows enough time for the digestive system to adjust to the new food without causing a sensitive stomach. Signs of a sensitive stomach are soft to loose stools, gas, and sometimes even diarrhea or vomiting. You should start off with 25% BLUE to 75% old food for one full week. In the second week increase to 50/50 for another full week and so on. By the fourth week, you should be able to use 100% BLUE. At any time you increase the amount of BLUE and notice a change in stools or gas occurs, lessen the amount of BLUE and slow down the transition a bit. Every pet is different. Some may take to the food right away and others will take longer. Age, breed, exercise and what they were eating previously can all play a role in how long it may take for their system to adjust.
A pet's system will eventually work itself out however this could take as long as a few months if not done slow enough. Not often, but in some cases the food may be too rich for your pet. This usually happens when they have any intolerance to an ingredient in the food. If you feel that maybe your pet may need a proper transition, it is never too late to do that. Also, make sure to follow the feeding guidelines on the side of the bag as overfeeding can cause digestive issues. You will notice that we may require a less amount a day than other foods. Make sure not to free feed our food. There are only natural preservatives in our formulas so once exposed to the air it will not stay as fresh. Stay away from canned foods while you are trying to transition as this may only add to the sensitivity of your pet's stomach. I hope this helps. "
Bookmarks