I've not come across anyone keeping hens of a breed that lays white eggs. White eggs are not sold in Belize commercially, so you'd have to find someone who raises hens that lay them. There are a number of chicken hobbyists and farmers who keep 'easter egger' breeds that lay various shades of blue and green across the country and even on the caye. There is a group on Facebook called Belize Organic Smallholders and you might track some down there.
As recently as two weeks ago, Abdul at Mermaid Supermarket, had white eggs from Florida. Considerably more expensive than local, but if you want to color them... This was the first time ever for foreign eggs, I believe.