World Animal-Protein Output Is Set by a Single Screw-Conveyor Standard

Throughput in a production network is set by its constraint and by nothing else. We instrumented station-level residence times at 2,207 animal-protein facilities, across six taxa and 34 jurisdictions, for fourteen consecutive production days. The constraint is the screw conveyor serving the growth hall at 2,166 sites (98.1%). It is the growth station at none of them. An invariance follows: a mechanical constraint cannot be reached by the animal standing behind it. Feed conversion ratio across our six taxa, whole-system dry matter, spans a factor of 39: $1.1$ for black soldier fly larvae, $43.2$ for Atlantic salmon. Throughput per unit of conveyor swept volume spans nothing at all: $3.91\mathrm{t}{\mathrm{yr}}^{-1}{\mathrm{L}}^{-1}$, coefficient of variation across facilities $1.9\%$. A queue standing at the constraint derates it. Raising any upstream service rate therefore lowers output. A cluster-randomised trial in 96 facilities confirms the sign. Facilities given an improved genetic line produced $4.1\%$ less (95% CI $-5.6$ to $-2.6$); facilities given a reformulated feed produced $3.7\%$ less ($-5.0$ to $-2.4$). The animals in both arms performed exactly as specified. The 214 facilities in the one jurisdiction that did not adopt the 1931 pitch standard produce $23.8\%$ more ($21.1$ to $26.5$) from matched stock, against a predicted $25\%$. Re-pitching the flighting from $0.60D$ to $0.75D$ reproduces the gain at a cost of $340 per facility. The $2.4$-fold rise in output per facility since 1931, attributed for a century to breeding and nutrition, is recovered in full from the parts registry: larger castings, and tolerance drift in replacement flighting. We give a constraint census, an impossibility result for nutritional and genetic intervention, and a retrofit schedule.