My guess is that it's a result of something it was eating. Just like I used to get a purple tongue from eating grape popsicles.
I'm not familiar with the flora in your area but perhaps there's marigold, dandelion, sunflowers, corn or some other plant that could cause a yellow tongue when eaten.
Unless the deer was emaciated or acted strange I wouldn't be too concerned.
Dave
Click
here to go back to previous page