I'm not sure yet, but I think I probably will skip book 5 Claire. It's Marco's first book where they sneak into Chapman's house as Ants and meet Visser 1 (Marco's mum) for the first time. I really like this book, but I suppose that's because it was the first Animorphs book I ever read. It would be kind of a shame to skip it.
On the other hand, I REALLY want to write my version of book 6! I have some great ideas and it's one I've wanted to write since I first started the series. Besides, I can't think of what I'd change in book 5 anyway, so it makes sense to skip it.
So unless anybody really wants to see me write book 5, I'll go ahead and skip it. If anyone does want me to write book 5, feel free to send me a PM with possible plot ideas.