How Big are Our Eggs, and Are They Going to Get Bigger?

One of our customers asked about egg size, expressing concern that they are smaller than others. With eggs being a natural product, there are going to be variations from one to the next. A recipe might call for eggs by count, but what really matters in making a consistent product is the weight of the egg.

In the past, we have not bothered sorting our eggs by size, being that we just don’t have very many to deal with. But since one of our favorite (and largest-volume) customers brought it up, it inspired us to reconsider. Perhaps we should sell to them by weight instead of by count.

The first step was to collect some data. What do our eggs weigh? Being that we don’t have one of these, the next best option was to weigh them on the scale we use for shipping. But what should eggs weigh anyway?

Fortunately, the USDA gives us some guidance on what eggs should weigh, or at least what we should call them based on their weight:

Size or Weight Class Minimum net weight per dozen
Jumbo 30 ounces
Extra Large 27 ounces
Large 24 ounces
Medium 21 ounces
Small 18 ounces
Peewee 15 ounces

Armed with the standards, we set out to weigh ours and get some averages.

We used a postage scale to weigh 40 eggs at a time. The eggs alone weighed 5 pounds and 3 ounces, which works out to an average of 25 ounces per dozen, not counting the cartons. In case you were wondering, our paper fiber carton weighs 2 ounces. The USDA numbers say “large” is more than 24 and less than 27 ounces, so we are comfortably in that size range.

Egg sizes do change throughout the laying cycle of the hen. The newest layers usually start with smaller eggs, as I would certainly prefer to do if I were going to take up laying eggs. The egg size increases as the hen gets older, but to a degree, the total number of eggs begins to diminish. My guess, which I can’t yet cite to be backed up by science, is that a hen only has the physiology to produce a relatively constant amount of egg mass. This is often the case with fruit trees, which have the roots and leaves to only yield a finite amount of fruit mass. It’s up to circumstances and management to determine whether that mass will be delivered in many small pieces, or fewer large pieces.

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