Honestly giving a pill to a chicken is very, very easy. I get nervous with liquids and syringes - though those aren't that hard either. But pills are laughably easy.
Break your pill in half.
Hold chicken on lap or counter top. Constrain wings with towel or just hug her close to you.
Pry open beak - that is the hardest bit.
Pop pill in towards the side - like in her cheek if she had one.
Tell her she is a good girl.
Repeat.
I have no idea why, but once it is inside their beak it just goes down the hatch.