More than a decade ago, Kirby Bros. stopped blending corn, oats, and bran and topping the concoction with molasses to satisfy the cravings of horses that had long been part of the South Jersey landscape. The 100-pound bag of horse feed, priced at $13.60, was the biggest seller, said Chuck Kirby, who inherited the 140-year-old family business and mill in Medford and operated it with his wife, Jan, and their son, Chaz.

As farms started to disappear, Chuck Kirby said, it made more sense to import livestock feed from Pennsylvania for their customers and to introduce a new line of food for pets, birds, and wildlife as suburbanites moved into the area.

But even that strategy was not enough to keep the Kirbys from announcing their decision to shut their doors on the last day of 2015.

The unusually warm December convinced the family that it was time to close, he said.

"It's heartbreaking," Jan Kirby, 63, said as loyal customers streamed in this week to say goodbye. Some wiped away tears and offered hugs after gazing one last time at the wares in the old-fashioned shop on Main Street with the creaky, uneven wooden floors. There were bags of sweet corn for deer, disposable "wee wee diapers" for dogs, a prefab chicken coop with windows, books on raising sheep, live worms, buck knives, and hardware for fencing. Livestock feed and hay and straw were also available in the back for delivery or pickup.

"We expect to have slow summers, because then there's a pasture that feeds the animals," Jan Kirby said. "But November and December came and we're still in summer mode. We kept hoping it would get cold" so the animals would need the feed - mixed with vitamins - that the Kirbys sell.

The animals also eat less when temperatures are moderate because they don't need to burn as many calories, she said.

Another challenge was the competition from big box stores and online markets that can sell pet products more cheaply, Kirby said.

"People don't realize small businesses are the backbone of the community," she said as the family German shepherd, Sophie, lazily greeted customers at the door.

"This is a huge loss for Medford," Joseph DiVincenzo said as he made his final purchase - a bag of deer food - on Monday. "If you live in Medford, you feed the deer and birds and the ducks. It's a town with a lot of woods and wildlife, and that's why people move here."

"I love this place. It's an institution," said Dan Padden of Southampton as he paid for dog food for his black Lab. He said that he would like to raise backyard chickens - if he can persuade his housing association to allow it - and that he would now have to search for another place that sells baby chicks and offers advice with their chicken feed.

Chuck Kirby, 66, a lifelong Medford resident, said the town recently passed an ordinance that lets residents raise up to nine backyard chickens. The backyard chicken trend and the new law, he said, led to a small surge in business. The shop sold organic chicken feed that was in demand because it produces healthier eggs.

Kirby Bros. also would sell about 1,000 baby chicks every spring, Jan Kirby said. "We were hoping to make it to chick season this year," she said, shaking her head sadly. The chicks were sold between March and June, she said, so that they would have time to mature in time for the winter.

Chaz Kirby, 40, has been working behind the counter of the Main Street shop and helping with deliveries since he was a teenager. He said the family recently discounted its prices to unload its wares but is still trying to figure out what to do with the building.

The business was established in 1875 by brothers Charles and William Kirby at a gristmill a few miles from the shop, which opened in the 1920s on Main Street. The gristmill is on the National Register of Historic Places, and was donated to the Medford Historical Society and turned into a museum.

Kirby said that customers who get regular deliveries of feed, straw, and hay are being referred to Woodstown Ice & Coal in Salem County; Allen's Feed in Tabernacle, Burlington County; and Reynolds Hay & Straw in Bordentown, Burlington County.

A letter posted on Facebook and signed by "The Kirby Family" said they decided "after much reflection" to close. "We have been able to look back with fondness on nearly every moment of our history. . . . We look forward to closing out the year reminiscing with faithful friends and customers."