It's actually just a bad habit you've allowed to continue...you bring the food and let them jump on you(they like to be high up and you're probably the tallest thing around).i imprinted my 3 baby chicks to think i'm their mother, and still at 14 weeks old, they still love to jump onto my back, shoulders, and even my head. i hypothesize that this is either an instinctual behavior to watch for danger or keep warm, or it's a method of bonding for the mother and chicks.
The bigger they get, the less 'cute' it is, IMO.