Hamdog,
I don't know where you are in life, but with one on the way, I will make the assumption that you're closer to early or middle than late... If I might make a suggestion... It sounds like a tractor is a "want", not a need. Your priorities are now for needs... Take care of those. For your want, I would recommend starting a savings account for a tractor. Put whatever you think you can afford for a payment in it EVERY month. Unless you have an absolute need, or perhaps work for it that includes getting paid so it pays it's own way, don't buy anything until you can pay cash.
IMO, if you can't afford even 20% down, you shouldn't be buying. Save your pennies, and you'll be there soon enough. OR perhaps a sweet deal will pop up. I've recently discovered FB Marketplace. No wonder there's not much on CL anymore...
Good luck, and Congratulations!!