At 3 to 4 inches in length, they're easy to spot and best removed by hand. Cats are notorious for eating pepper seedlings. Dogs are notorious for chasing cats. Unfortunately, they also enjoy digging in the garden. Birds eat peppers.
Cats eat birds.
It's a vicious circle. It seems everyone wants to know. The answer depends on your motivation. For example, jalape os, serranos and New Mexico chiles are often picked in their mature green stage for use in fresh salsas and cooked sauces. But they also can be allowed to ripen to red before picking, after which most varieties are dried for later use.