The industrial incineration of aviary manure is still far from the concept of using its ash residuals for nutrient uptake by plants and most of these materials are landfilled under futile fixed cost. Aviary manure includes poultry litter mixed with different aviary bedding materials or laying hens manure, which may be burned using different incineration technologies and conditions. This study aims to determine the comparative characterisation of P-rich ash residues sampled at Gures Energy (Turkey) fluidized bed combustion of laying hens manure and at Campoaves (Portugal) chain grate stoker combustion of rice husk poultry litter. The effect of different fuels and different combustion systems on P speciation in ash was investigated: the characterisation of global samples (bottom ash (BA), economiser fly ash (FAECO), cyclone fly ash (FACYC)) and respective size-fractions were done chemically (proximate and elemental analysis by X-ray fluorescence-XRF-and Inductively Coupled Plasma Mass Spectroscopy - ICP-MS), morphologically (detailed imaging and X-ray micro analysis by Scanning Electron Microscopy-Energy-Dispersive X-ray spectrometry-SEM-EDS) and mineralogically (X-ray diffraction-XRD). Phosphorus was detected in Gures ashes mainly as hydroxyapatite crystals alongside with CaCO3 relics and CaO, while Campoaves ash fractions contained P also as Na-K-Mg phosphate and major amounts of rice husk relics including unburnt char and silica phases. Both Gures and Campoaves ashes are complex but the combustion of aviary manure under these setting conditions appears to be promising for P recovery owing to their high P content and limited trace elements respecting the limitations imposed by EU legislation for fertilisers applications.