how much pasture is required

Question
My horses are 31" and under, and my breeder thought that the largest one is probably 200#> I am trying to convince the city that the grass is not the best and to allow me to keep them in the present space, going down to 2 horses if needed. Any sources you can give me to support that would be appreciated.
-------------------------------------------
The text above is a follow-up to ...

-----Question-----
I have 3 minis, one just a weanling. We brought them home and have them in a paddock area that is part of our backyard, where they seem to be thriving. They have a shelter, heated water tank, hayrack and though there is less then 1/2 acre fenced right now, they are able to run and play. We feed twice a day with alfalfa hay and grain. There is grass, but I am not sure if it will grow well next spring in this space. In applying for a variance to keep them here, I am asked to provide more information on minimum pasture requirements. I have heard everything from..fine in your residential backyard to 3 per acre. I am using them as emotional support animals, as I have MS with associated depression, and therefore may be allowed to keep them here, or at least 2 of them, if I can meet the requirements. It would also be helpful to have a formula to gauge their weight, 1 unit is about 1000 lbs, and and a mini is only a fraction of that. Thank-you, Barb
-----Answer-----
The best way to gauge weight is to get a weight tape. They are usually pretty accurate within a few pounds. The amount of land requirements vary from state to state and is based on a large sized horse. An acre per large horse is what our requirement in oregon is. I figure the average mini between 32-34 inches is between 250-300 pounds if they are not little butter balls. So I would divide that up into the average horse weight of 1000 pouonds which would  be a quarter acre per which sounds like you have enough for 2. The truth is as long as they can play and run I personally would rather not have grass. Those who have nice pastures always worry about weight and foundering.I just feed a good quality hay three times a day and then I can monitor what they get controlling their weight. The minis are great companions and are wonderful friends for people with depression and handicaps. They sure cheer me up when I need them too. Good luck and hope that helps. Happy Holidays! Melissa

Answer
This is a little out of my expertise it is probably a matter of city ordinances. I would probably start first by going around to all of my neighbors those who would be affected by your horses and get them to sign a petition to let you keep them there. I do know that the city requires you to clean up all manure and bag and dispose of it. I would then find out your citys laws and contact your citys mayor or one of those people who are in the commissioners office or something and find out how you go about getting a varience or what if anything you can do to be able to keep them. I know of two of the 4 H kids who have two minis on a small lot and they take them out for walks ect. I know they don't have any pasture to speak of but something that you can always bring up to the city folks is the fact that in california some of the horse facilities have their horses both big and small dry loted on sand in paddocks so whats the diff?? Wish I knew more about the laws. Where are you located>> I have a group I belong to with all mini people maybe someone has some more info for you! Melissa