Did the dendrobium come from hawaii? or somewhere like Lowes or home depot? If so, this is typical... at least for me. They are fine! Just keep a normal watering regiment of 7-10 days and bright light. The new growth will take over! The leaves on older canes just do that when transported to a new home. They have to 'adjust' to your care. I wouldn't worry. Can you post a picture of the whole plant?
Yep it's the "Let's freak out the new owner" thing Dens like to do. I have one from the Formosae section that dropped all but 4-5 of it's leaves in less than 5 days. I was pretty new to orchids at the time and it seriously freaked me out. It's alive and well and going strong today.
I'm really glad I posted a thread about this!!! Thanks everyone for making me feel better. I'm not sure where it came from exactly Chris, I bought it at a Kroger and they usually have some pretty good stuff there. I think what really did it was taking it home. It was maybe around 20 degrees that night and I'm sure it really made my Den mad!! It just looked really suspicious to me, given the way the leaves turned yellow. I thought for sure I brought some bacterial or fungal infection up in my house!!! Thanks again, everyone!! I LOVE THE ORCHID BOARD!!!!!!