A few questions... I have never added any new chickens to an existing flock. I always just sold all and started new. Anyway, I have several EE's and I am thinking of adding a few Welsummers. The ones I have now, the EE's, are about 3 months old. 1.The EE's have had MAreks vaccinations but the Welsummers have not. Would you vaccinate the newcommers also? There are a lot of chicken farms, and others that have chickens around here. 2. Should I seperate them for a while? 3. I have a choice of getting some Welsummers that are a little younger than my EE's, or just a couple months older. Which is best?