How many students and faculty members on the campus of Cal State San Marcos today realize that the previous occupants of their campus were millions of chickens, residing on one of the largest chicken ranches in the world?
From 1945 to 1985 the Prohoroff Poultry Farm covered 568 acres near Highway 78 and Twin Oaks Valley Road. Here’s an undated aerial photo of the farm from the archives of the San Marcos Historical Society:
All those white-roofed buildings were chicken houses where the laying hens were kept, according to an interview I had with a granddaughter of Terenty Prohoroff, the Russian immigrant who founded the farm. Those houses made up the largest portion of the ranch, with a separate section for young chicks.
At its peak the farm housed some two million chickens and produced some 329 million eggs annually. Contemporary newspaper accounts described it as the biggest chicken ranch in the county and one of the largest in the world. Farmers and agricultural departments from as far away as Australia and Japan visited the place.
The ranch also had a plant for processing fertilizer, as you’d expect from an operation generating almost 11 million pounds of chicken manure each month. The flower-growing operations of the Ecke Family of Encinitas was one of the biggest customers for Prohoroff fertilizer.
In 1985 the Prohoroff family sold the land to developers who in turn sold part of the acreage to the state of California for the construction of today’s Cal State San Marcos campus.
Sources for this post included the San Marcos Historical Society archives and interviews with Prohoroff family members.
Get Updates Automatically-Become A Follower of the San Diego History Seeker
You can get weekly updates of San Diego History Seeker automatically in your email by clicking on the “Follow” button in the lower right corner of the blog page. You’ll then get an email asking you to confirm. Once you confirm you’ll be an active follower.


