I do have a scale if I need to use it. How exactly would you measure a milligram?
You would use a one ml (cc) syringe. One ml of paste has 100mg of fenbendazole, so 1/2 syringe (0.5ml) has 50mg fenbendazole. You said you have one that weighs 1 pound, right? This is the formula I use.
Weight in pounds divided by 2.2 (converts to kg) times the mg per kg you want to use divided by the number of mg in one ml. So the formula for a one pound bird look like this:
1 / 2.2 x 50 / 100 = 0.23ml of paste(I would round up to 0.25ml)
A five pound bird looks like this:
5 / 2.2 x 50 /100 = 1.14ml of paste
Make sense?