Brew some weak tea, and let the towels soak in the tea. Wring, let dry. This should do the trick!

I dye things quite a bit and I would have to see the towels and see what tones are in the towels. Do they need to be lightened and then tinted? How will that effect the red in the roosters. Teas come in all different shades but will be a very temporary stain if you are washing frequently. What is the fabric? Natural vs synthetic? If trying to preserve the colors of the roosters, it might be more difficult.

Roosters are red, but if they were more brown-red it would be fine. Fabric is 100% good quality cotton, thick waffle weave. Sounds like a smidge of yellow dye is best bet. Hmm.

Wouldn't the yellow give the roosters an orange tint?

Dyes don't always mix like pure colors. It is easy to get muddy browns and grays. You might have to remove color before you apply color. You can't necessarily change the color from tan to cream by just adding more dye as the new dye doesn't cover the old but adds to it not always in a predictable way. It all depends on the colors and how dark they are. Even if a towel is 100% cotton, if you have an appliqué or embroidery, the thread or part of the appliqué may may react differently than the rest of the towel. If it is polyester thread and embroidery it may not bleach or take new dye so may not change much or could change completely.

I would evaluate the risk of ruining the towels vs the ? chance of having them come out like you want.

I have used herbal dyes( teas, flowers, fruits, vegetables, leaves) extensively and they are actually easier to apply evenly because they don't have the chemicals to make the dye "hold" like commercial dyes do. They do often appear as blotchy because they are applied that way on purpose to make something look older. At one time with the "country look" of the 1980s people did this with tea in a very heavy handed way.