(until the ) late 1870s. ... the demand for fresh eggs was largely satisfied (to the extent it could be) by importing eggs from great distances, or by seabird eggs, gathered from the giant (but fast declining) colony of murres that roosted on the Farallon Islands, 30 miles due west of San Francisco.
No local source of chicken feed made it hard for mass production of eggs:
chicken feed was so expensive that Boston eggs, shipped around the Horn, and murre eggs from the Farallones were cheaper than hen’s eggs after the cost of feed.
? Bad chicken feed leading to disease that wiped out the chickens.
the American Menu has the story of importing food via clipper ships.
And ten there was this: collecting eggs from seabird nesting sites on islands nearby.
The Egg War is the name given to an 1863 conflict between rival egging companies on the Farallon Islands, 25 miles off San Francisco. It was the culmination of several years of tension between the Pacific Egg Company (also known as the Farallon Egg Company), which claimed the right to collect the eggs on the islands, and several rival firms. The resulting violence claimed two lives, but left the Egg Company in sole control of the islands' eggs. Its victory was short lived; the company sold the rights to use the islands in the late 1870s and the federal government removed all egging companies from the islands in 1881.
A website on the seabirds of Farralon Islands