Fescue is a grass which is cut and cured, then baled into hay. Here in the South, it's commonly used, but has a fungus associated with it that can be harmful. I'd ask the local extension agent about it. They have studied it extensively in their forage classes and can give you advise. The fescue is only dangerous at certain times of the year when the endophyte is present on the growing grass.

Fescues are cool season grasses. There are tall bunching grasses named tall fescue and fine shorter fescues named creeping red, hard, chewings and sheep fescue. They are all shade tolerant, stay green all year, and have very good drought resistance.

If you can get 100% Timothy hay it won't be too rich. It's the alfalfa and clover in your hay that is too rich for them. Did you know there is a Farmlife forum? You can ask other Alpaca owners over there what they feed their animals.