If the Reagan administration's proposed welfare cuts are enacted, they may have an unintended victim -- Church's Fried Chicken.

What is at work is what you might call trickle-up economics -- a financial blow to a particular group of consumers that may have an impact on companies that serve their needs.

"A number of our customers are in the low-income-family grouping. If there are cutbacks on welfare, it could conceivably impact some of our sales," said William J. Storm, senior vice president for finance for Church's.

The first of the month -- when welfare and Social Security recipients receive their checks and the eagle flies for some federal employes and others on a monthly salary -- is the fried chicken chain's biggest sales day. If it falls on a Friday, "it's a bonanza," said Storm.

"We are concerned over the longer term that Church's clientele could be negatively affected by the Reagan administration's attempt to reduce the give-away payments to lower-income and, to a large degree, center-city residents," said a recent Dean Witter Reynolds Inc. analysis of the company's earnings prospects.

Church's, a chain with about a dozen stores in this area, is based in San Antonio, Tex. Its strength is in the Southeast, Southwest and Midwest, and the chain is growing in the New York area.

Storm does not expect the impact from the budget cuts to be profound, but it is serious enough for the company to take it into consideration as it views its prospects. "We probably have a larger proportion of our stores in the inner-city market" than other fast-food operations, he said.

Church's also differs from other fried-chicken franchises in that it cuts its chickens on the premises, a job considered perilous enough by the Occupational Safety and Health Administration to prevent the chain from hiring teenagers as the others do.

Storm said Church's has no figures on how many of its customers might be welfare recipients but had a strong general impression that they are a substantial segment.