I'm so sorry to hear that Lucas still has diarrhea. I'm glad that you found out that Biddy has roundworms and that he's much better. I always thought that kittens were more prone to roundworms. My cat Pepper had them when he was a kitten but he didn't have diarrhea. The only time that my cats ever had a diarrhea problem was when they were sick with an URI. Actually it was only Pepper because he got worse instead of better. He got so sick that I thought I was going to loose him. This was only last year. Good luck with the diarrhea problem. Maybe Lucas has a sensitive stomach and his food aggrevates his stomach. I sure hope that he feels better soon.