where to get Vaccinations?

vaccinations are given from day old onwards and are available in batches of 1000, so as a backyard poultry keeper the chances are - a)  your birds are too old and b) you don't have enough birds to warrant giving these vaccinations. Also there are so many you would need to give. You would need to buy the gun to administer some (others are given in their water). Realistically unless you are going to spend a lot of money and time doing this and keep thousands of birds it isn't a viable thing to do.
Please note that myco can be passed down from the hen to the egg so breeding with a bird that has had myco is a nono 

and can still carry Mareks but not develope the tumours (but can pass it on)..... distant memory so could be wrong

the only problems I have had have been from birds bought in - all died  . I did have myco in one bird but she only ever had the one bout and never any recurrences so all in all just be careful where you buy your stock whether eggs or birds. Visit the place they come from and if in any doubt do not buy (wish I had followed my own advice).