Putting UK Grey Squirrels on the Pill?

The Grey squirrel was introduced to the UK as a North American 'novelty' in the 1870s. Grey squirrels boomed here. This alien species' introduction has had very negative impacts on local forestry. Greys have also almost wiped out the smaller resident Red squirrel. Greys, not only out compete Reds, they harbour Squirrelpox. Squirrelpox has little impact on the Greys but infection is often fatal to the Reds. The UK Squirrel Accord are advocating a novel way of controlling (i.e. reducing) UK Grey squirrel populations (https://www.theguardian.com/environment/2022/jul/11/oral-contraceptives-could-help-reduce-grey-squirrel-numbers-research-finds). The UK Squirrel Accord propose introducing special feeding hoppers, with weighed doors, to woodland locations. The hoppers are designed to exclude other wildlife but they allow access by 70% of local Grey squirrels. Once in the hoppers, the squirrels can eat a bait, laced with a specially-developed oral contraceptive. This would reduce successful breeding by some Grey squirrels. There may, however, be problems with this approach. The 30% of Greys that are unable to obtain access to the hoppers, could still breed. There are also masses of Greys in UK urban areas, who could repopulate any areas, where hoppers are employed.