In agricultural landscapes, habitat quality is a crucial issue for the conservation of biodiversity. Several kinds of data suggest that farm characteristics are important driver of habitat quality, but to date a few studies have investigated whether management intensity is related to farm size. The question whether biodiversity may benefit from a few large versus several small farms is still unclear. In a grassland landscape, with high priority for bird species conservation, we tackle this question by 1) analysing a large data set on management practices in 574 grassland fields within a large range of farm sizes and 2) assessing the impact of management on habitat quality. Three types of grassland managements were identified through multivariate analysis showing an increasing level of intensity. Higher habitat quality was related to medium and low management intensity. However, no relationship was established between farm size and management intensity. We conjecture that a threshold on farm size may however exist with potential detrimental effects on biodiversity due to homogenisation of habitats. Our results are discussed in the light of other farm functions in the local economies and we conjecture that the maintenance of a variety of farm sizes may be needed to reconcile productive, environmental and social functions assigned to agriculture.