With bow rockers the problem is
worse as the angles between the legs, body and bow are wide compared to swing stand horses where the load bearing joints are
more in line.
This horse had all four legs loose and two had also pushed out of their original mortices and broken the body blocks. In such cases the leg joint and body needs to be rebuilt.
The rotted wood has to be cut out, the inside surfaces made perfectly flat and a new block or blocks have to be made to fit the space exactly. This is important if the new joint is to be strong as its strength depends on a large matching surface area for gluing. Glues said to be good gap fillers will not give as good a repair as careful joinery so that there are no gaps to fill.