Hazleton Laboratories Corp. reported record earnings of $835,000 (25 cents per share) for its third quarter ended March 31 compared with earnings of $500,000 (20 cents) for the same period last year.

The Vienna, Va., biological research company reported revenues for the quarter of $10.663 million compared with $10.868 million the year before. Nine-month revenues were $32.8 million compared with $32.210 a year before. Net income was more than $2 million compared with $1.5 million a year before.

Bresler & Reiner Inc., a D.C.-based real estate development and residential construction firm, reported net income of $1.998 million $1.81) a share) for the three months ended March 31 compared with $165,000 (15 cents) for the same period in 1980. Revenues were $6.178 million compared with $2.428 million a year before.

Chairman Charles S. Bresler said that the increase in profits largely reflects a previously announced gain from prepayment of a mortgage on an apartment project sold in 1979 and a related brokerage commission. The gain in revenues reflected both that transaction and increased condominium sales, he said.

Heck's Inc., a diversified regional retailer and wholesaler based in Charleston, W.Va., reported first-quarter net income of $1.227 million (13 cents a share) compared with $1302 (13 cents) for the same quarter in the previous year. Both results were adjusted to reflect a three-for-two stock split effective May 29, 1981.

Net income for the first quarter in 1980 included a nonrecurring pretax gain from the sale of a fixed asset of $870,000 (5 cents). No such gain was available in this year's first quarter. Revenues were a record $95.615 million compared with $87.006 million in 1980.