Companies generally hire seasoned iOS developers because of various reasons such as experience, flexibility, availability, good communication and most important is their understanding of various domains and industries. You must hire ios developer
either from top portals or from companies having over 10 years of experience in this field. The iOS developer should have real-time experience on Objective-C or Swift and Cocoa touch, iOS framework such as core data, core animation, familiarity with RESTful APIs
to connect iOS application, knowledge on UI/UX, understanding of code versioning tools such as Git, Mercurial or SVN.