You can tell alot about a chickens health by looking at their poo.
http://chat.allotment.org.uk/index.php?topic=17568.0
Green poo could be as simple as something she's eaten; also keep in mind that a chicken with worms doesn't usually have them show up in the poo until the wormload is...
The only part I disagree with is feeding the eggs back to the hens. Any residual wormer in the eggs would be like giving the chickens a partial worming again. I discard the eggs in the trash for two weeks.
I use valbazen. You give a 1/2 cc orally, undiluted, for standard hens; 1/4 cc for...