Many mature, non-pregnant, non-lactating equids are often kept in circumstances where they are expected to perform only light physical work or activity eg: a childs pony. Consequently their maintenance energy and protein needs can often be met at very restricted feed intake levels. Conversely, when they are housed during the winter months it is believed desirable to manage such animals on unrestricted ad libitum feeding regimes in order to allow the animals to exhibit their natural feed intake pattern and consume forage on a little and often basis throughout the daily feeding period. However, ad libitum access to the diet may lead to such animals becoming excessively fat. These conflicting needs of low energy and protein requirement coupled with the desirability of unrestricted access to the diet could both be met, at least in part, if a low quality forage is available ad libitum. This study examines the voluntary feed intake and apparent digestibility in vivo of a mature threshed grass hay offered ad libitum and determines its ability to meet the predicted energy and protein needs of mature ponies.