You need to keep them hydrated. Are they drinking water? If not you'll need to force some on them, do you have a syringe?
I don't know if I would try tuna
That might make their tummies upset.
Do you have a food processer? If so, you can put the rice and chicken in the processer and it will chop it all up together, so they can't pick out the chicken.
Also, I would cook a chicken breast like this: in a frying pan, put a tiny drop of oil or cooking spray, put the chicken in for a few minutes on both sides (the meat will start to turn white) then pour about 1/2 cup of water in and cover with the lid, you'll have to turn the chicken a few times, but it shouldn't take long to cook. Once cooked put the chicken to side (and puree it if you have the food processer, if not, cut it up) - Now back to the pan, if you have a fine drainer, drain the 'gross' stuff, but keep the broth - Yummy! You'll need to add a little more water to the broth, but you can use this to pour on their food and even get them to drink it as it will help to hydrate.
Keep us posted
