Before you even begin to think about starting a small, part-time, speciality poultry enterprise, you need to consider disease control. Keeping a healthy flock is important not only to your own farm, but to other farms, both small and commercial size. Put it first and foremost on your list of things to do.
The first thing to consider is your facilities. Does your set up make it easier to clean? If not, cleaning and sanitation becomes a chore you don't want to do. Free range operations are a problem as well. Just because birds are on open range doesn't mean that there is no need to worry about manure handling. Design everything to be easy to take care of and easy to clean, wash down and disinfect.
Free range operations are more susceptible to diseases transferred by wild birds and migratory waterfowl. Does your property attract unwanted visitors? There is no possible way anyone can recommend a good disease prevention program if your property has a pond on it that is not separate from your operation. The risk that visiting waterfowl bring are just too big to take. I would not consider a small poultry operation near open water of any kind. What about sources of feed? Do you have wild birds visiting the feeders? If so, you are not just wasting feed, but you are risking your flock.
Do not keep mixed flocks. If you are going to market eggs, then everything else avian MUST go. That includes pet birds, leftover birds from old flocks, broilers, turkeys, ducks or whatever. Raise only the birds that you intend to use to make products. If you think it's okay to leave the pet birds that have been around your farm for years, think again! They could carry disease from your older flock to your replacement flock. I like to see operations have some down time between flocks so that all disease carrying organisms will disappear.
Consider your sources of stock. Do you have a source of DISEASE FREE stock? Just because you order chicks from a hatchery does not mean they come free of diseases. Most small hatcheries test for Salmonella pullorum because they are required by law. But what about other diseases like Mycoplasma galliscepticum (MG)? If you go to a bird swap or auction to purchase your stock, then just close up your business now. Sooner or later, you'll bring something home that you didn't want. Buy from known suppliers who can prove that they have disease free stock.
Do you have a plan for vaccination? Just because you buy day-old chicks from a hatchery that vaccinated the birds, doesn't mean your birds are vaccinated for everything. Most hatcheries will vaccinate for Marek's Disease because it's difficult to store and ship the vaccine, but there are many other diseases that you should consider. People don't take disease control in their speciality operations seriously. However, no farm should even consider raising specialty birds without a disease control plan.