Poo stuck to their bottom doesn't necessarily indicate worms. You can clean her bottom up and then trim the fluff a bit, if she's having trouble in that dept.
To answer your question on worming, some folks never worm. Others only worm after a positive fecal float done by the vet. I choose to worm once a year with a broad spectrum wormer. Two I have used are valbazen (albendazole) and ivermectin. Both are cattle wormers used "off label". There's a two week withdrawel with both.
Usually round worms can be seen in their droppings. If you determine they really do have worms, there are many remedies. One that I`m quite fond of and you can still eat the eggs, is Cayenne Pepper.
It`s a natural wormer. Mix it heavily with your feed to turn it red. Pepper in the front, worms run out the back. Chickens don`t have the heat receptors like most critters, so they eat it up. Worms, on the other hand, heh, heh. You can still eat the eggs. Repeat in 10 days to get the new worms.......Pop
I only worm my birds if I see any signs. If I have to de-worm, I use Verm-x it is a natural wormer and there is no egg withdrawal period. I have used Wazine but there is a 2 week withdrawal period for the eggs and also if you are processing meat birds, you should wait two weeks before processing after you worm the birds.. http://www.vermx.com