>> I... was wondering if it would be a good idea (or is it standard
>> practice) to drill a hole or some other opening above the excluder for
>> the workers to enter and exit more easily?
 
> It is definitely not standard practice in my part of the world.  Your
> bees will deposit their pollen  in the supers instead of in the brood
> chamber...
 
Here in Alberta, we do have some holes in supers above excluders and have
never found much, if any, pollen in the supers.  We have almost always
used excluders and found that anytime we left them off that our work
increased drastically and the crops were smaller.
 
The main disadvantage of too many holes in a hive  is that bees do not
store honey as well near entrances, and that moreover draughts may cause
the bees to withdraw to the brood chambers during a cool spell.  These
effects can result in earlier capping and thinner combs as well as less
honey being stored in the supers.
 
Another disadvantage is that -- under some conditions -- the bees will be
very unpleasant to remove using a blower, since they are used to flying
from a hole in a tall white thing and,  when you have taken the hive apart
and are trying to blow out bees you are the tallest white thing around :)
 
Although we have played with various ventillation schemes and entrances
for access to the supers over the last quarter century, we have concluded
that two 1" auger holes in each brood chamber and a wide open entrance
at the floor give very good results.  I'm not even sure that the wide open
entrance is necessary and was intrigued by Vince's recent post.
 
As far as the bees getting through excluders is concerned, it is seldom a
problem with strong hives.  The only warning here is that the brood
chambers must not exceed two standards in volume.  If the broods are made
of three or more standards, the bees may find they have enough
honey storage below the excluder, become honey bound, and never go
through.  If a single standard brood box is used, excluders are no
impediment at all.
 
We feel that *reversing* doubles before adding the excluder is very wise.
Although most hives will go through anyhow, having brood in contact with
the excluder's lower surface makes the combs above much more interesting
to the bees.
 
Allen