I gave a look at the slaughterhouse, prices aren't far to be perfect, just a bit too high because in the filltype you used a "seasonal" variation as it was crop so at a point you can sale the meat 3 times the price of the animal. With 24 cows you can then earn 144000 € in a month (normal mode). Meat shouldn't have seasonal factor (or not high, like wood ) and I just saw the same problem with products like mayonnaise with a too big gap in the year, after all we don't pay our mustard or ketchup more expensive in winter ;) Goats and sheeps don't have the same price (300vs500) but produce same amout of meat so balancing is impossible with only one prod line. All in all a cow milk should produce less than other cows as they cost 50% less. It's possible to use the cows the month after buying them (maybe the same, didn't think to try), maybe a minimum of 2 months feeding would be better even if 20 months is a bit high ? ).
Ideally animals should produce less liters (but better price then to balance) because a pig of 150kg giving 500l of meat seems really weird, and don't hesitate to increase the fat for cows, 15% of the meat isn't insane (4% actually ), it will help later for soap recipe which is actually impossible to follow.
Finally, the biggest problem I found is that we can't bring chickens as there is no trailer for that. You should say we need https://www.farming-simulator.com/mod.php?mod_id=320983&title=fs2025 for your map (or making you own with the vanilla in just adding chiçcken load/unload) if we want to produce chicken meat.