Feeding them some in water via a small 5ml syringe you can get from your chemist shop is actually easier than you think, so long as you can have someone else hold them at the shoulder on a flat surface to stop their wings flapping, then you just bend back their head and open their beak, my hens have always given in quite easily to this actually, give them a couple of squirts of the liquid - not too much at a time or they will gurggle it up. You'll be a bit nervous first few times but after that you'll do it just fine... do it with confidence, it'll be quicker and less traumatic for the hen. You can do it. Good luck.