There are two things you can do. One is to ignore them and come back next year and see how they did. The other is to pray a lot.
Cookies, rounds cut from logs, are inherintly unstable. The reason is that the distance shrinking wood has to travel on the outside is much greater than the distance it must travel on the inside. It's like a man who eats apple pies every day for a year and tries to wear the same shirt.
The best that can be done is to dry it super slowly and hope that mold or mildew don't attack it.
There are techniques for repairing cookies though. One that I've heard is to have more than one cookie cut from adjoining pieces of trunk so that the grains are the same. Score the cookies with a saw in different places to get them to crack on the score. After they have dried, cut out the scored piece in the shape of a wedge and replace it with a matching piece from one of the other cookies.