I just finished my first year, and I bought myself a Suffolk sheepy. C: I know that the jersey cows appear randomly, but when do the new chickens appear? Are they random as well, or do they have a set date that they come out?
I also got the sullfolk right at the beginning of Spring, probably day 1 or 2. The silkie appeared a few days later. And the jersey were available at the end of Spring, when I had returned to Konohana and wasn't able to buy it anymore.