Canopy Cover and Herbage Accumulation of Fourteen Grassland Species When Stocked with Chickens

Abstract

Maintaining intact vegetation in the outdoor run of chickens (Gallus gallus domesticus) can be difficult due to intense stresses such as defoliation and concentrated manure. The aim of this study was to determine the extent to which damage-tolerant plant species can improve canopy cover. In a 2-yr field experiment, we subjected 14 disturbance-tolerant grassland plant species (nine grasses and five forbs) to stocking with laying hens for short (1-d), medium (2-d), and long (3-d) periods in a rotational stocking system. The species differed strongly in resistance (canopy cover and density of tillers and vegetation growing points) and resilience (herbage accumulation) to stocking. Repeated stocking but not duration of stocking had a significant effect on herbage accumulation and canopy cover in most of the species. Canopy cover decreased with repeated stocking in the majority of the tested species. In most forbs, increasing stocking duration significantly decreased the density of vegetation growing points; in most grass species, this factor had no significant effect on tiller density. Our results indicated that grasses are generally more suitable for an outdoor chicken run than forbs. The best performance was recorded for Schedonorus phoenix (Scop.) Holub and Poa supina (Schrad.), with >80% canopy cover, constant tiller density, and herbage accumulation of >4.8 g dry matter m−2 d−1 after repeated 3-d stocking. We conclude that the use of disturbance-tolerant grassland species will improve swards in outdoor chicken runs.