In which level you actually start to need all producing animals?
I'm at level 43 at the moment and have been very conservative in adding new producing animals. I currently have 12 chickens, 10 cows and pigs, five sheep and four goats. When my barn space is tight, I leave my chickens to wait egg collecting for long times. When I have more room, I try to keep eggs a highest number item in my barn to make little people to ask them. I sell milk regularly and bacon has been basically hazardous waste in my farm, though now I have couple products I like to produce for sale that actually need bacon. Pigs just look so pitiful both when hungry and when waiting for a collect that I don't have heart to leave them like that. Wool is something I once in the blue moon am left wanting, but it is easy to buy, and cheap too. And no one wants to buy wool products anyway, so not a big loss, if my loom goes without work for hour or two now and then. Goat milk I at times sell, if I or my friends don't get goat milk boats in some time.
When I visit other farms, I notice most higher level farms have all possible animals, but then again, so have most in my level. At the moment I'm making good coins from selling lots of animal feed and would loathe to give that away and have to produce more feed for my own animals, so I'm not planning adding up my animal count, and they take so much space too. But in which point will I have to do it?