Is it a good omen to see a peacock?

That would depend entirely on your take on peacocks.

Some cultures consider them good luck. Others see them as unlucky.

The peacock is thought to represent an over-blown pride, certain royalty, and some god-heads.

The feathers of a peacock are unlucky unless presented as a gift.

I have friends that keep peacocks as "guard" animals, as they are very noisy and can be aggressive with strangers. It can be very unlucky to wonder into their yard at times.