Most delta trikes put their power out through the right wheel. It would make sense that the right wheel would have spoke breakage if, as is probably the case, the wheel is under-tensioned. That would allow the wheel to flex when power is applied and eventually flexing spokes would break. If that's a common problem for that trike, it might be a good idea to take a new one to a bike shop to have the wheels tensioned and trued. It's a relatively small charge per wheel, and not something that a big-box store assembler is going to be capable of.