I've only seen that once as yet, and it may have been a French source (one of the Rouxs I suspect). It make sense, because the 10g difference between the top and bottom of each size band can really add up in a recipe that calls for, say, 6 medium eggs. 6x53 = 318, while 6x62 = 372, and the difference is a seventh medium size egg.I see more often recipes giving the weight of the required eggs along with the number
My flock's eggs range from mid 40s (Maria, Araucana so technically LF, and some pullets' early eggs) up to low 80s (hybrids, all LF) which would be labelled small to extra large in supermarket-speak here. When I get one below 43g, which would count as 'extra-small', I keep it for own use, in case customers think they've been short-changed. I try to make sure there's a good mix of sizes as well as colours in every carton I sell, and some customers really appreciate it, perhaps for your reason; I'll have to ask why, next time someone mentions it!a standard egg is too big and I don't often want one, whereas as a 30-40g egg is perfect
I don't think that's a feature of bantam v large fowl. I suspect it's not of 'breed' either, just the genetics of the individual hen. A huge yoke was so noticeable with Eve's eggs (Norfolk Grey LF) that I took of a photo of it:the proportion of yolk to white