"The farmers work with cows and chickens."
Translation:I contadini lavorano con le mucche ed i polli.
Sorry, I should have been clearer! Using ed or e between one word that ends in a vowel and another that begins with a vowel is personal choice. You can use ed if you think the sounds would become confusing (mucche e elefanti : ed would be more appropriate so your listener knows there is an and in there and not just a list of animals)
Ed however is not necessary before a consonant. This is somewhat similar to the use of a and an in English. An is only used to enhance flow and clarity...it prevents most people from saying a apple. Hope that makes more sense!