Inheritance

2 of my sisters are executors of my late fathers will. There are 4 children, farm and all assets are to be shared equally between us. The executors have written to me, ordering me to remove my childrens pony from otherwise idle land within 4 weeks, or they will "Dispose"of him. My father was a huge horseman and he bought the pony for my children in 2011. The pony has been on the family farm since then. I'm not sure which way to go with this, I don't have any place for the pony to go nor do I have the energy or funds to end up in court with this nonsense. Technically the pony might be part of my fathers estate, then the executors can take him, sell him, put him to sleep, whatever they want. There is no probate yet due to an o/s legal claim against my father/his estate. Should I respond? Should I get rid of wee pony? Should i defy them and leave him there, they are doing it to be vindictive.