In poultry manure (PM), the nutrients are high due to uric acid and undigested protein. While the nutrients availability varies in fresh and composted PM. A green house study was conducted at Agronomic Research Farm, University of Agriculture, Faisalabad, Pakistan, during 2009 to examine the availability of nitrogen (N) to maize (Zea mays L.) hybrids with non composted and composted PM under various irrigation regimes. The experiment was conducted in green house using completely randomized design with factorial arrangement and replicated five times. Two maize hybrids; a drought tolerant (Monsanto 919) and a drought sensitive (FH-810), previously screened, were planted at two irrigation regimes, (75% field capacity and100% field capacity). Nitrogen availability was higher in composted poultry manure than the non-composted poultry manure  which eventually resulted in more plant height (147.60 cm), leaf area index (4.99), photosynthesis (21.82 µ mol m^-2 s^-1) and transpiration rate (8.50 m mol m^-2 s^-1). However,maximum days to tasseling were recorded in non composted PM.