I have 10 chickens. 4 that are alittle over a year, 2 who are abt. 5 mo and 4 that are abt. 4 1/2 mo. I know the 4 abt a yr. I can worm but are the other 6 too young? Also I would really like to get Valzaben but both my husband and I are unemployed and really can't afford that much of an expense but I hear that othing else works. Is this true or is there something. I have read where someone uses one product then uses another in abt 10 days.