I'm so sorry!
I know EXACTLY what you feel like... Almost the exact same thing happened to me a year ago, except Peep was the only chicken we had.
He was the sixth member of our family and considered us his flock, and was always most happy whenever he was with all of us together. He made it his personal mission to seek each of us out each morning and "dance" for us, and would run across several yards to greet my sister and brother coming back from school to 'lead' them back home. He tried to mimick everything we did, looking in the cabinet for a snack, playing with his big red ball, even sitting on the couch with us while we watched movies. And always wanting to share our food, of course!
When we'd left we'd promised to come back in a few hours. We were minutes too late. Minutes away from being able to say goodbye. I can not remember one time when he was sad, because whenever one of us was around, he was happy. But when he died he was alone, waiting for us to come back for him. That pains me horribly even still. He was only one year old.
I know it's hard to lose a beloved pet, believe me I do. But the best thing you can do is think of all of the best times you had with her and be happy knowing that she was. Write down every little detail you can think of, so you can always know how to refresh those wonderful memories.
I'll pray for you