There are carcass collection stations in some states and even compost facilities specifically for taking in animals from small scale farming operations. A d I understand state laws very
Missouri law says burial is legal but it is also the least desirable means of disposal. And if you live in town you will have a hard time meeting the guidelines for doing it legally. Specifically the rules on how far from property lines and neighbors
The location of a burial site must be:
At least 300 feet from any wells, surface water intake structures, public drinking water supply lakes, springs or sinkholes.
At least 50 feet from property lines.
At least 300 feet from any existing neighboring residence.
More than 100 feet from any body of surface water, such as a stream, lake, pond or intermittent stream.
Law also says in regards to sending animals to the dump
” Landfills are permitted to accept dead animals under Chapter 260, RSMo. Modern sanitary landfills are designed and operated to prevent leaching into groundwater or surface waters. The drawback of landfills is that they are only for disposing, not for recycling, and landfill space is becoming scarce. Even though a landfill is permitted to accept dead animals, it may not be the policy of the landfill operator.”