The Arizal brings from the
Rishonim that an ostrich is unique in that it does not sit on its eggs
nor does it place them high in a tree. The ostrich buries its eggs in
the sand and with its powerful vision it watches them from afar. The
eggs are able to develop from the heat of its gaze.
Emden says that because of the special power of the ostrich's eye, some
Sefardi kehilos have a minhag to hang ostrich eggs in Shul. The
ostrich egg symbolizes the power in a persons eye wherever he glances.
Seeing these eggs inspire a person to have kavana and not to look
around during davening. (Otzer Hayedios Rav Y. Michel Stern)