Hi @Chicken_Thighs Are you having trouble with worms in your chickens? Can you take a poop sample to your vet for testing so you can get confirmation of worms and the type that you may be dealing with?What is the best wormer to use I thought DE? .. do i need to use something in addition to that?
i have an Orphington doing the same, her sister born at the same time (December) has been laying daily for a couple of months the other one seems to be losing weight?
You mention that one is laying eggs - but not the other one? If she is not laying eggs is she molting, does she have any swelling/bloat or feeling of fluid in her abdomen? Is she lethargic and not eating? Check to see if her crop is emptying overnight. There are so many reasons why a chicken can lose weight, worms can cause weight loss, but exploring all your options is a good idea.
DE is not effective as a dewormer. If testing is not possible, general deworming instructions would be to use Valbazen or Fenbendazole (Safeguard, Panacur).
Valbazen dosage is 1/2 ml orally and then repeated in 10days for each chicken and Fenbendazole (Safeguard, Panacur) is 1/4 ml per lb. for 5days in a row. Egg withdrawal period for both would be 14days after last treatment.