I don't know whether to call it affection, but they do things that endear them to me, haha.
My rooster greets me, does the shuffle dance for me when I haven't been out in a while, offers me the odd leaf, allows stroking and close contact. He let's me do anything with him, his babies, and his hens without question. I take that as deep acceptance, and it means a lot to me.
The hens are sweethearts in their own way. I don't have the time to spend with them that I'd like, and they are less bold than the rooster, but something I love is when I sit or crouch with them and they gather for a preening party. It's really something to just go out, sit and wait, and here they come to chill with me. They do occasionally use beak scrapes on my clothes or shoes when they feel especially greedy for a treat, use me as a beakwipe on occasion, and one really loves feather scritches/grooming and will beg for it by scratching my boots with her feet.
I've had snugglers and close friends in a childhood flock when I had all the time to spend with them. I miss that, but am grateful for the little gestures I receive even now. They are truly special animals. Maybe in my retirement I can have all that again one day...