Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to vaccinate chickens [title] Give chicks their first vaccinations at the right time. [step] Different vaccines need to be given at different times in a chicken's life. Most vaccines are given soon after the chicks have hatched.

Ending1: In some cases it's still a few weeks before the hens become pregnant. [substeps] For some breeds, however, vaccines can be taken when the puppies are about six weeks old. Ending2: Always talk to a veterinarian before vaccinating if you have never vaccinated a chicken before. Common vaccinations include : [substeps] E.coli: given at one-day-old. Ending3: Occasionally, vaccinating a goose can also be done during the transition period of time when chickens can still be independent. [substeps] Most vaccines are given only once the chicks have been weaned from their mother. Ending4: [substeps] Even if the baby chickens die during incubation, they should still receive their first vaccinations at least as early as they are young. Your new chick will usually be vaccinated at an early age, especially if she is younger than three or four years old, as will many 12-month chickens.

Answer format: ending1/ending2/ending3/ending4