I need to give wormer to my horse in a few days since he hasn't been done yet. I'm just wandering if it's alright to do it when it will be really hot that day? I'm thinking on doing it tomorrow morning around 9:30 since the barn owner feeds at 7 - 7:30am. The day is going to be around 99 degrees and supposed to be pretty humid so it will feel way over 100. Should I wait and do it on a cooler day?