Hi Liz,
I’m glad to hear he likes the Nutri-Berries so much! The amount varies by bird, even 2 birds of the same species might have different needs. An average range is at least 6 and up to 12 daily. Your goal should be for him to eat as many as he wants, as long as he is eating all of each berry. If he picks out a few bits and wastes the rest, he won’t be getting the full benefit of the food. Make sure he is eating the berries and not just tearing them up. If you see he is wasting a lot, then reduce the number you give him at a time. When he has consumed those, give him some more.
Thank you for asking Lafeber,
Brenda