Some members of Congress are calling it the "Great Chicken Flap," but none of the participants in the dispute is cackling.

The flap started when Sen. William S. Cohen (R-Maine) learned that some of his colleagues had forwarded letters from their constituents to the Department of Housing and Urban Development, protesting a proposed $500,000 Urban Development Action Grant for Lewiston, Maine. If approved, the grant would help Lewiston reopen a poultry plant that closed last spring when its operating company went bust, costing the city 250 jobs.

The letters were prompted by the National Broiler Council, which represents three-fourths of the poultry producers in the nation and doesn't believe the chicken market needs any more competition.

"I have never in my nine years in Congress witnessed such an intervention . . . to defeat a project wholly outside the borders of their states or districts," Cohen squawked in an angry floor speech.

While Cohen refused to name his letter-writing peers, HUD said it had received comments from Reps. Trent Lott (R-Miss.), Bo Ginn (D-Ga.), Jack T. Brinkley (D-Ga.), Wyche Fowler Jr. (D-Ga.), G. V. (Sonny) Montgomery (D-Miss.), John P. Hammerschmidt (R-Ark.) and Sens. Howell Heflin (D-Ala.) and Thad Cochran (R-Miss.).

Cohen accused his colleagues of trying to make the "prosperity of one region contingent on the suffering of another." He also introduced legislation to strip the council of its tax-exempt status--a move, he said, that would teach it a lesson.

HUD spokesman Jack Flynn, meanwhile, claimed the congressional letters really won't make any difference when HUD makes a decision about the grant this fall. The grant process, he said, is designed to be politics-proof.