I had a sick hen and was worried about whether or not she was drinking enough water. I figured out an easy way to force feed her water using a syringe (without the needle).
I mixed up a little cup of water with some electrolytes and found a small syringe dropper.
Using my thumb and pointer finger on my left hand, I gently pinched her waddle (the little flap of skin under a chicken’s chin). Then using the tip of my ring finger, also on my left hand, I pushed open the top of her beak.
Once the chicken’s beak is propped open, you can give the hen a sip of water using the syringe dropper.
All the chicken needs is a few drops, then release her waddle and beak to let her swallow.
Once you put the liquid in her beak, she should swallow it on her own just fine. Just be very gentle.
Here’s a video of me making the hen drink water, using the dropper method.