Chiggers measure a mere 1/150th of an inch, and so are nearly impossible to see with the human eye. But there is an easy way to sample your yard for chiggers, if you're concerned about a possible chigger infestation. Be sure, of course, to wear appropriate clothing and repellent whenever you walk through an area that may have chiggers.
Chiggers prefer moist, shady areas with thick vegetation, so focus your sampling efforts on these places in your yard. Don't bother sampling for chiggers in areas that get full sun, or where you keep the lawn mowed short.
To sample your yard for chiggers, you'll need one or more squares of black cardboard, each about 6 inches by 6 inches. Stand the cardboard squares on edge in areas where you suspect chiggers may be. Leave the squares in place for several minutes.
Look closely at the cardboard once you've left it for a few minutes. If chiggers are present, they will climb up the cardboard and gather near the top. The chiggers will be tiny, and either red or yellow in color.
If you find a heavy infestation of chiggers in an area of your yard, you may choose to implement some control measures to eliminate them. At the very least, you'll want to avoid walking through those areas of your yard.