A kilogram is equal to 2.2 lb, not 3 lb. So, the chicken should receive 1 ml per pound.3lb = 1 kg, so you should probably give a little less than 2ml. I wouldn't know how many times a day though.
Do you know if she is impacted or blocked? Does the crop go down any at night and is there poop on the drop board in the morning? If she is impacted, your problems are not going to go away. If there is some but not enough, it may be a slow moving crop which is also because of a blockage somewhere. I would empty the sour crop, flush it with water and empty again. A crop tube will be handy in this situation. Then feel if there is any large mass in the crop that may be preventing movement. If she is blocked in the crop, it is sometimes fixable. If the blockage is further down the digestive track, the best you can hope for is if you put enough liquids in her (like extra water, a little olive oil or some lubricant) for a few days, the blockage may move on it's own. If there is a mass in the crop you can try massaging it to break it up. Do this a couple of times a day for a few days. Maybe a little olive oil in the crop when you do this. If its a mass of grass or hay in there, I have found that nothing but surgery will fix that.