Force feeding anything is traumatic - for us as well as the chicken. If you have to do it, make it a two person activity. That way there is four hands to hold the chicken still, open her beak, put the tube in, press the plunger and to change tubes if you have to feed more than one. It would really help if you had octopus heritage!
Here's what we did...
First - weigh your chickens a few times a year. Its a really good way to decide if a chicken is sick. If its lost a significant amount of weight, there's a high chance its not well in some way. And no, its not weird to weigh your chickens. Hard work but not weird! (Try it just after they have gone to bed. Set up your kitchen scales in the pen on a flat surface. Pop a washing basket with a towel in it on top and "zero" the scales. Take the chicken off her roost and pop the her in, note the weight and pop her back on the perch. Wave to the neighbours looking incredulously over the fence. Grab the next one and so on. Like I said, not weird at all)
In our case we went to the a great bird vet - Brisbane Bird Vet - to get a diagnosis and all the bits that we needed. Dr Adrian is a fantastic vet and spent the time showing us what to do (and made us have a go) in the surgery before we took everything home.
This video is really bad but if you have to do it will give you an idea of what's involved.
We mixed up 3 tablespoons of Roudy Bush handfeeding mix with 120mls of warm water. We thought cold mix straight into the belly might be a bit rough when you aren't feeling the best. Also less metabolic energy for her to warm it up. In a weak chicken you want them to use as few precious calories as possible. The crop can easily hold 250mls of liquid according to the vet even though we were only putting in 120mls. Its a dense high energy mix and 120mls should keep her system busy digesting for about 12 hours.
We then set up the syringes with the mixture in them and put the feeding tube onto the first syringe before we went and got the chicken. I held her with my thumbs over the top of her wings and my fingers around her legs so I total control of her. Aracana's are small chickens and so this is easy to do with them. If you have a big struggling chicken, wrap it really firmly in a towel and hold the whole bundle really firmly. When we first started doing this it was easier as she didn't struggle as she was too sick and too hurt. After a fortnight it started to become a struggle and once she started eating her self we gave it up - Waaaaay to traumatic for all of us! If the chicken can struggle a lot, I don't think they are too sick!
I lift her slightly off the ground to stop her from having any traction. My husband then holds her head and forces her beak open and with two fingers (Thumb and index over the top) holds them open. You need to make sure her neck is stretched not bent. The tube wont go down otherwise. Once we have the beak open, I hold her against me with one hand and free up the other hand.
I use my now spare hand to hold the weight of the syringe as my husband gently feeds the attached tube about 3/4 of its length down her throat. (One hand still holding her beak, the other one the tube.) Then I move my syringe hand down to the part where it joins the tube so that when he presses the plunger (he has bigger hands than me) its doesn't force the tube off and squirt mixture everywhere except where you want it. It also gives him some thing for brace against. If the mixture is thick, its hard to get moving.
All this time you have to make sure that she still has her neck as stretched as you can. If she struggles once the tube is in, she is uncomfortable. Try stretching the neck before taking it out and starting again. Putting the tube in a couple of times stresses everyone. This video is our second attempt that night and you can see she isn't happy to have another go.
Once the first syringe is empty, I hold the orange part of the tube with that spare hand and my husband pulls the syringe out and picks up the other one and inserts it in the tube using my hand to push against and then he pushes the plunger on the second syringe and in goes the rest of her dinner! The whole time he is holding her beak open and holding her neck straight with the other. Its defiantly a two person operation.
Once the second syringe is empty, its easy to release the beak and gently lower the chicken back onto the table and pull the tube out. The chicken is usually very happy too!
Wash all the equipment thoroughly. I used detergent as there seemed to be a "fatty or oily" residue left behind and I didn't want bacteria or mould growing in the tube or syringes. You could sterilise them using baby bottle stuff but I figured a good wash and dry in the sun would be ok. The mouth and crop are not sterile environments so you don't have to go overboard. (see what type language you pick up if you hang out at the vets long enough?)
We had to do this twice a day for two weeks before time and nourishment did their thing. Each batch of feeding mixture has a prescribed 2mls of vet obtained painkiller to relive her distress. We actually had her inside in a box for all this time but next time I would put her in the isolation pen as she lost her high ranking position in the flock and is now at the bottom. Three weeks was too long for her to be away.
If you have any questions about this - feel free to leave me a comment. Its quite hard to imagine how to go about it until you've done it a few times!
Green-ness: Not sure I can find a green angle for this activity...
Frugal-ness: Not anything close to frugal. I paid $165 for the consult, pathology, feed, tube and syringes. But as she is back laying and part of the flock, I think its well worth it.
Time cost: An hour at the vet and about 10 minute for each feed.
Skill level: You need confidence and motivation to start with. The skill kicks in about day five.
Fun -ness: Not fun at all until the results start to show!