This paper analyses the dynamics in the farm size distribution for The Netherlands, Germany, Poland and Hungary. A (non-)stationary Markov model approach is used. The transition probabilities are explained by a set of exogenous (policy) variables. The models are estimated using an information theoretical approach, including non-sample (prior) information. The models can be used to simulate the impact of alternative dairy policies on the dairy sector structure. For all countries there is an autonomous decline in farm numbers over time (implying increase in average farm size). This trend continues irrespective of the EU dairy policy type. For both Hungary and Poland the role of the subsistence sector is expected to substantially decrease over time.