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The indicator amino acid oxidation (IAAO) method allows the determination of amino acid requirements under conditions of low growth rate as found in pre-laying broiler breeder pullets. Cobb 500 breeder pullets (20 wk old; 2290 [+ or -] 280 g, n = 4) were adapted (6 d) to a pelleted, purified control diet containing all nutrients at [greater than or equal to] 110% of NRC recommendations. After recovery from surgery for implantation of a jugular catheter, each bird was fed, in random order, test diets containing one of nine levels of lysine (0.48, 0.96, 1.92, 2.88, 3.84, 4.80, 7.68, 9.60 and 14.40 g/kg of diet). Indicator oxidation was determined during 4-h primed (74 kBq/kg body), constant infusions (44 kBq * [h.sup.-1] * kg [body.sup.-1]) of L-[1-[sup.14]C]phenylalanine. Using the breakpoint of a one-slope broken-line model, the lysine requirement was determined to be 4.88 [+ or -] 0.96 g/kg of diet or 366 [+ or -] 72 mg * [hen.sup.-1] * [d.sup.-1] with an upper 95% CI of 6.40 g/kg of diet or 480 mg * [hen.sup.-1] * [d.sup.-1]. IAAO allows determination of individual bird amino acid requirements for specific ages and types of birds over short periods of time and enables more accurate broiler breeder pullet diet formulation. KEY WORDS: * individual requirement * maintenance requirement * broiler breeder pullet * indicator amino acid oxidation * continuous infusion