The common rule of thumb for non commercial operation is one tractor per 2 acres. This counts riding lawn mowers in the total. You might not qualify since you are talking about actually putting some hay up.
1) Never number your tractors
2) Give them names instead
3) NEVER park them close together, it is too easy for someone to count them
You can always get one or two of each color, have a few small ones, a few medium and at least one too big to do much close to the house.
You will need to make sure you have hydro and gear, open station and cab, R1 and R4 tires, etc.
Now let's talk about some implements.
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2) you have to have at least one flail mower
3) at least one snowblower
4) at least a 40x60x16 shop to keep things out of the weather. This can be a problem, you will have to be careful not to park the tractors too close together, lest they be counted....
5) for haying, you will need a sickle mower, disc mower, round baler, big square baler and small bales. Of course, you will need a long triple axle trailer to haul the hay from the field to the hay barn (forget to mention will need a hay barn also).
... and so on, you get the idea.
Now about buying the tractors, make sure you get a good deal and finance it all at 0% for at least 7 years. You can make at least $5,000 for each $20,000 worth of tractor financed (if 5 years), should be able to make considerable more when financing at 0% for 7 or more years.
The more I think about it, size does matter. You need a track hoe also. I'll bet you forgot about the need to built a pond now that you have land. There are several really good threads on pond building, just know if it is a big hole you are digging, it will take lots of machines and time.
For each project, do a financial analysis, determine how many tools you can justify to buy and keep while still costing less than paying someone else to do the project.
Let me share what we did,
We started with a Kubota
L3130 with FEL. Within the first month we added a 72" rear mount finish mower and some quick attach front pallet forks. We settled on a used (432 hrs) Kubota
L3130 because we liked the frame size and it fit our budget. If I had more budget, we would have looked at more tractors in this frame size, perhaps even one with a cab. We would have loved to get more hp but it was not affordable at this time. I don't think you will find one tractor that does all things you want well when you add the haying into the mix. You're gonna need at least one big tractor, get it with everything you think you will need, especially cab and rear remotes. We're not doing any hay at this point so don't need bigger, but you will.
Just remember, you can't have too many tractors or tools. Good luck, you are going to be spending some serious money.