I have used Kaytee Exact for quite some time as it seems to be readily available from Petco/PetSmart locally. However, I have also recently tried Psittacus and Lafeber's Nutri Start. The Kaytee and Psittacus seemed about the same, but the Psittacus was a bit easier to mix. What is a great formula that is good at putting a healthy weight on Linnies and what does everyone here use? Thanks!