Hello All,
> I manage an observation hive that is kept indoors.

You have to indeed manage a observation hive.  Many times before the end of
our state fair ( eleven days) we have to remove and rebuild one or both of
the OH.  They are quite a commitment.

> Every year so far we have had to replace our bees (first because they
> swarmed and recently because they got sick (dysentery) and the population
> dropped).

There is a new book out on observation hives available from Mid-Con
Agrimarketing (1-800-547-1392).  I haven't yet read the book but looks
interesting.  In the mid 90's Bee Culture ran a year long set of articles on
setting up and maintaining a OH..


> This is contrary to the "living, working hive" that we are trying to
> present.

Keeping a year round OH can be compared keeping a fih tank.  Quite a bit to
the project other than setting up and watching only.   If not there is
always a market for used OH.

> Would less sunlight help?  Is it the warm temperature they don't like?

NEVER let direct sunlight hit the  observation hive glass The insides of
hives are normally dark plus observation hives have trouble exhausting heat.
Sincerely,
Bob Harrison
Odessa, Missouri

Ps. I assume you have got a couple of other hives you can pull brood, etc.
from if needed.  If not I would start a hive or two to help maintain the OH.