Simply cut the cardstock into the shape of a donkey's face. Then use colored markers to decorate accordingly. Write the kitty party details on the flip side. You can even take help of various online messaging apps like whatsapp and facebook for sending invitations to the guests. You can take help of various emojis like donkey, food and so on. You can write the following lines in your message.
HEE HAW
HEE HAW
WE ARE HAVING
A DONKEY THEME KITTY PARTY
ON 17TH JUNE AT STUSH CLUB.