Considering selling call duck hatching eggs

[SharW75]

We have a nice little flock of call ducks of various colors that my daughter shows at our local fair. Currently, we are incubating 7 and the majority of them are developing nicely. One of our hens also hatched out ducklings last year, so the fertility is very good. We are considering selling fertile hatching eggs, probably locally, rather than shipping. What would be a good price to ask? A semi-local auction occasionally has them and they go for anywhere from $30-$60 per dozen, sometimes more. What sells better--dozens, or half dozens?