At this time none. But this is something (water soluble dewormer) I have struggled with finding since they took wazine off the market. I prefer to keep these products on hand rather than wait for the problem and not be able to treat it promptly.Notice that it's not approved for chickens or other poultry.
Fenbendazole is approved for use in chickens, with no egg withdrawal, so there's no reason to go off label with this product.
What intestinal parasites do your birds have?
FARAD link didn't really work.It is only approved at a very low dose for five days that works on ascarids only. Doesn't really matter which product as long as you can get the dosage down that low.
Notice it says water soluable but regular Fenbendazole can be mixed in with feed for the same effect as noted here. Anything higher than that dose is not approved for use in chickens.