The European Commission requested the European Food Safety Authority (EFSA) to gather and assess all data available and produce two scientific opinions on: The influence of genetic parameters on the welfare and the resistance to stress of commercial broilers; and The welfare aspects of the management and housing of the grand-parent and parent stocks raised and kept for breeding purposes. In order to ensure that the opinions were based on comprehensive, relevant and up-to-date information, the Animal Health and Welfare (AHAW) Unit undertook a consultation with its stakeholders through a Technical Meeting at the inception of the assessment (Autumn 2009) followed by a public Web-consultation on draft outputs (Spring 2010). Representatives of the poultry industry, breeding companies, research groups, NGOs, national and international institutions attended the Technical Meeting. The participants exchanged views on scientific and technical aspects related to welfare of broilers, with special focus on data availability, data sources, and clarification of the request from the European Commission. Participants agreed that poultry breeding for meat is a dynamic industry and stressed the importance of having access to the most recent data. It was concluded that the lack of a harmonised system for data collation may hamper the assessment. A web-based public consultation on the draft scientific report was organised in the spring of 2010 and online published invitation for submission of written comments by deadline set on 14 April 2010. The consultation produced some valuable comments, information and data. These were incorporated into the draft report when the AHAW Panel considered their scientific basis to be valid and robust. Base one this draft report the two scientific opinions were developed (on the influence of genetic selection on the welfare and resistance to stress of commercial broilers ; and the welfare of housing and management for broiler breeders ).