Are you planting an annual clover or a perennial clover....the chicory is a perennial. As such the chicory is going to focus on growing roots first. Spring planting can be done, but if you get some summer stress the young plants may not survive. Fall planting won't produce much to interest the deer, until the following year, but you increase your chances of success in my opinion. The deer here hammer the chicory come late october/early november for some reason. If you plant in the fall you can also plant cereal grains and brassica to provide some fall food.....just remember your real intent is for next year. Oats and brassica will act as annuals and provide food in the fall and will be dead when your chicory comes to life again in the spring. An annual clover will die as well, where a perennial one will survive and many folks mix perennial clovers and chicory as the chicory like the N the clover produces. Spring planting can also stir up more weed seeds and typically spraying herbicides on young plants is a bad idea for their survival.....fall planting may work the same seeds, but the cooler temps will limit the growth of the weeds in most cases.
