Lavender is feeding other Pets the Skill Foods, but her own kitty is not being fed many of them...
Flounder explains that this is because lots of people have cats as their Greeter Pets (although he can't understand why?), and people may already have run out of the Skill Foods for cats before they get to Lavender's Page!
Flounder suggests that Lavender makes her kitty her Visitor Pet instead of her Greeter Pet, and adopts a dog or a cow for her Greeter Pet (the one that gets fed), because there are not as many Greeter dogs or cows on people's Pet Pages.
Flounder shows Lavender the "Edit" button at the top of her Pet Page, and tells Lavender to click on this and scroll down the page to see if she already has any other pets.
Lavender can then use the double arrow (switch around), moon (hibernate), sun (wake up), "Hi" (make into the Greeter Pet) and shield (make into the Visitor Pet) icons to change which of her pets greets and visits other pets!