lice infestation - permethrin 10%

[ironsfamilyfarm]

Well it's spring and I noticed my girls have lice! I bought some permethrin 10% and was planning to use it in a garden sprayer to treat them and the coop. My sprayer is small, only 51 ounces...can anyone tell me how much permethrin needs to be used? I'm terrible at math and just want to get advise from someone who has used it! Thank you!