I am President of a start-up company.  The CEO and Founder and myself
are devout Christians, and since we have hired mostly friends and
family to work with us so far, the entire office is Christian.  We
feel very strongly about the morals and values we have instilled in
this company because of our strong faith.  We would never discriminate
in hiring anyone based on their religion.  However, we would like to
continue to run the company based on our Christian principles.  There
is a prayer we use to start our meetings.  My question is, since we
are a privately owned company, do we have the right to continue to
read that prayer, regardless of whether new employees object to it or
not?  And is that something we should or can address during
interviews?  (Not whether they are Christian, but if they would object
to working in a Christian environment and hearing a Christian prayer.)

You ask: "[S]ince we are a privately owned company, do we have the
right to continue to read that prayer, regardless of whether new
employees object to it or not?"

The fact that you are privately owned does not necessarily help you
here.  The key issue is whether or not you expressly or tacitly
practice religious discrimination through creation of a "hostile work
environment."  So, if you hire a new employee and they choose not to
participate in company prayers, you may not actively or constructively
treat that employee in a less favorable manner than you treat any
other employee. To do so might expose your company to a lawsuit for
religious discrimination.  As you know, religious preferences and
practices are protected under federal law.  Thus, if the person chose
to step out while the prayer was being offered or otherwise refused to
participate, you would not be able to terminate their employment based
on that behavior without risk of a lawsuit for wrongful termination
and religious discrimination.

You also ask: "And is that something we should or can address during
interviews?  (Not whether they are Christian, but if they would object
to working in a Christian environment and hearing a Christian
prayer.)"  You can ask the question, i.e., ask if they would be
offended by certain of your company-endorsed religious practices, but
it would be unwise to base a hiring decision on an unfavorable
response.  For example, if you had two equally qualified candidates
and one said they would object and one said they would not, if you
rejected the first candidate based solely on that criteria that could
be problematic.

You need to consult with an employment law lawyer in your
jurisdiction, but as a general rule, you may advise candidates of this
practice before you hire them, but to base a hiring decision on how
favorably they react to the idea is risky.

Good for you, packleader. I once (unknowingly) took a job and ended up
working for two pastors and a pastor's wife (ELCA types) of the Phila
synod. While they did not have prayer time or anything, I do believe
that working there was exactly what I needed. That was a long time ago
and, while I practice no denomination, I do have a personal
relationship with Him.

I'm a firm believer that nothing happens by mistake. So, somehow, even
if something DOES occur that's negative, I'm sure there would be a
reason for it. I think it's terrific that you are concerned, tho.

:)
Hope you don't mind me poking my 2 cents in.