Mrs K, from now on, I'm just going to PM you what I want to say and let you say it. You can put things so much better than I can. This is my situation. I rarely have more than 2 dozen birds on my place at once, the only money I really have in them is feed and what we put into building the coops. I don't regularly bring in new birds, don't go to swaps and meets, and other than the day-old Freedom Rangers I got last year, and the half dozen pullets I got in Oct. have not brought new birds in for about 3 years. I raise barnyard mutts and am content with that. If I had a high-dollar purebred flock, or a lot of chickens, I'd definitely do things differently.It is a gamble. And a big consideration is the value of the flock you currently have. A couple of birds is just not as big a gamble financially as a flock of 100 or more. Some people on here would grieve terribly, and that makes it a bigger gamble too.
I belong to another chicken group, and they make my blood run cold, getting birds from swaps and auctions, where you bring a bird (stress of transport) put them in cages next to strange birds (exposed to God Knows what) have countless people walk by, who one would assume, many have birds of their own, and who knows what is on them..... These are bio-security nightmares, and the chance of exposure to disease is skyrocketing. There are a lot of people who do this, and are risking a great deal.
On the other hand, if my friend has chickens 30 miles from me, none of her neighbors have chickens, she is an experienced poultier, and takes reasonable care of her birds. She has a reasonable set up, yes I am taking a chance, but nothing compared to the risks above. I have often added birds with no problems from these types of set ups.
Many people pretend to quarantine, but if you are not doing it right, you are just pretending, it is not like horseshoes or grenades, close does not count.
If the risk is too much, then don't add birds, unless you can keep a very strict quarantine.
Mrs K