not horsey work but when my husband works bank holidays he gets paid double rate. Therefore I would expect to pay twice as much as normal for xmas and nyd.
Both yards i have worked at no liveries were done on xmas day or new years day apart from one lady who was on full cos of a broken leg!! It was enough hassle doing the riding school ponies and YO's and my own. I would expect at least double pay plus several bottles of wine/chocolates
At my old yard, there was me and 1 other livery. YO fed and turned them all out Chirstmas morning, other livery did boxing day and I did New Year's, so a fair split of the mornings.