Andrew Harris, the charity's director of fundraising, said: "The hunt is a really fun way for families, locals and tourists alike to enjoy the age-old Easter egg hunt tradition on a huge scale and as a giant exhibition of modern art, whilst raising vital funds for some of the most vulnerable children across Scotland and the UK.
"We appeal to whoever poached our egg to return it to us soon. And in the meantime, the hunt, the fun and the fundraising goes on."
The remaining eggs can be found in St Enoch Square, outside Buchanan Galleries and in some shops and museums.
A Big Egg Hunt was held in London for the first time last year and three eggs went missing, although they were all later returned.
This year's event began in London on February 12 and also took place in Birmingham, Liverpool and Manchester. After Glasgow, the eggs will be taken to London's Covent Garden in time for Easter.