The hen's egg: Shell cracking in eggs dropped on cage floors coated with plastic or zinc

Synopsis A sequential method of estimating the mean and variance or the drop height (h 50) at which the shells of 50% of eggs crack when dropped on a cage floor was used at each of four locations on each of five cage floors, made of 2.05 mm diameter (14 SWG) steel wire, that were similar save in respect of the coating on the wire. The coatings were: none, zinc at 2.7 g/m and polyvinyl chloride (PVC) at 2.0, 3.0 or 6.6 g/m. Relative to the uncoated floor the zinc‐coated one was markedly worse in respect of shell cracking and the PVC‐coated floors were marginally better. The relationship of h 50 to the weight of PVG coating was curvilinear, with an optimum at about 4 g/m. The method of estimation proved very efficient.