Do you free range your existing flock? It's recommended to quarantine new poultry for a month. That means separate living quarters and run, by as much space as you can keep between the new and old birds. Be sure to wash hands well before moving between both flocks. Quarantine best practice also recommends change of clothing and shoes between flocks. This may be difficult for the small BYF keeper, and understandably so, but the risk is there of the new birds bringing in a latent disease or parasites, that may not show up immediately. Worse case, the new birds are carriers, and will not exhibit signs of disease, but can still infect your existing flock with deadly results. So, that being said, If I were integrating after quarantine, I'd bring one of my old birds from the middle of the pecking order, and introduce that bird to the new birds for a week, then if all went well, then add the 3 birds to the old flock. This gives you a chance to see if the old bird picks up any disease from the new birds, and gives them a flock mate to help with the final integration. It also may be prudent to give the new birds a topical (external) parasite treatment as soon as you get them. Free range opportunities allow an almost seamless integration of new birds.
