Development and test of an egg collecting device for floor eggs in loose housing systems for laying hens

Following the European ban on traditional cages, loose housing systems were introduced to increase behavioural freedom and welfare of the animals. A consequence of these systems is that a few percent of the hens tend to lay their eggs not in the nest but in the litter on the floor. These floor eggs lead to economic losses due to quality degradation and more work for the farmer since their collection is required. As this task is labour-intensive and executed under unfavourable conditions (presence of fine dust, bending over to collect the eggs), automation of this work is desired. An autonomous robotic collection system will require an end-effector capable of collecting floor eggs under the conditions found in commercial poultry houses nowadays. To enable simple and continuous collection, a new type of end-effector was developed using a methodical design process. Requirements from floor egg locations, characteristics of eggs and functionality of the end-effector were considered in the design. The design process yielded an end-effector consisting of a curved metal spiral which rolls over the litter surface. When touching an egg, the shape of the egg and the applied force open the spiral, and the egg is collected by entering the spiral. After collection, eggs are unloaded by rotating the spiral in reverse direction and moving the eggs outwards to an unloading or storage device. The size of the spiral (length and wire diameter) and the spiral curvature angle are adjustable in the design to accommodate different egg sizes. A prototype end-effector was tested in commercial poultry houses, containing white and brown hens of different ages. Two test runs, with variations in the design, were done. In the first test, combinations of two wire diameters, two spiral lengths and three spiral curvatures were tested on 50 white and 50 brown eggs each, to determine the most suitable designs for collecting floor eggs. In the second test, these settings were evaluated on a larger number of eggs, to determine success rate, egg damage and to investigate whether the end-effector is capable of dealing with the conditions in which floor eggs are found, like location and clustered eggs. In the first test, it was found that a 4 mm spiral that was slightly over-stretched (opening angle between 90 and 120 degrees) collected 81 to 98 % of the eggs during the first attempt. For a 5 mm spiral, this was up to 88%, whereas 6 to 46% was broken during collection. In the full-scale second test, it became clear that eggs in open areas or along obstacles could be collected without any problems. Eggs in corners or close to electric fences could not be reached. Also, clustered eggs were difficult to collect as well as eggs buried in the litter. The developed end-effector can be regarded as simple and effective tool for collecting floor eggs, with very good results in open areas and along objects. The collection of eggs in corners, in groups or that are buried require further development of the collection device.