We had a signed lease the first year. The landlord then said he didn't want to sign a lease going into the next year. We really didn't agree but that's just the way things ended up. We continue to pay a third party a money order each month. Now its at the end of this month an the landlord called saying we had to be out within 30 days. We have been here 18 months, in Missouri, an have a 7 year old child, an also 15 head of cattle. We have so much stuff there's no possible way to be out in this time. What rights do we have. They have given no reason for us to be out.

The landlord needs to give you WRITTEN notice that includes a full rental period. So if your rental period is a calendar month, he has to give you written notice prior to 10/31 to be out by 12/1.
Missouri Notice Requirements to Terminate a Month-to-Month Tenancy | Nolo.com

Other than that I don't see any other legal protection. However, these rules generally refer to residential property. Since you stated you have cattle, this might come under farm or commercial property. I suggest you consult a local real estate attorney to see if this gives you any additional rights.

Having been there 18 months and having a 7 yr old doesn't give you any leeway.