To avoid overpaying wages and screwing up the growth pattern: PLAY REALTIME!!!! those fields are quite long to work!!!
There's one annoying bug on this map(and I think it's common with 4x maps), the Grimme S-710 picker-uper doesn't pick material from ground... not sure it works in the animals manure pits, and can't remember if I ever tried as It's been present from the beginning...
To put put straw/grass/hay at cows: enter their barn and go along them and you'll have the trigger to unload, or there a feeder, with a water through on the right side of their pasture(on the side of the TMR mixer).
About the equipment suggestion I made:
transfer money to buy 1 set of equipements. If you have a good timing, you'll get plenty of money to buy more very soon.
If you have the BigBud DLC and/or Kuhn DLC, It's the best equipments for this map!
The Horsh DLC(the free one, I hope you got it!) Agrovation vehicules&equipments are a good addition too.
1 warning about seasons, if you use the GEO I suggested, it begins in early spring, with snow and frozen grass... so if you buy and setup animals before activating it, make sure you have enough straw(Cows), Grass, hay(cows/sheeps) and grains/root_Fruits(Pigs) to handle the spring, mid and late summer, because with seasons there's only 1 harvest per year!
About the average profits, with starter fields: I couldn't find any precise stats, as I am using Seasons since its release...
Normal mode: 1 M $+ with good(no high needs) prices
Hard mode: 500k+ with average prices
If you need any help, tricks or hints on this map PM me, I'll be happy to provide.
I played since V1(which was kinda annoying to play with lots of fences and quite a few bugs), and I must have played pretty much over 200hrs if haven't passed the 300s on this map.