Yes...it happens:

Delayed Opening

Delayed Opening - Short-lived periods of time in the delay of the opening bell referred to the delayed opening. This may last for a few minutes or continue for several hours. Generally, there are extenuating circumstances making it prudent to delay the start of the trading day. The situations vary, but it does occur. There are three known reasons for this delay. The first, delaying the opening of the exchange to trading due to disparity in the day or hours before. The second, the disparity between supply and demand, and the third is determining all the factors and assess the...