There are other forms of Marek's than the one that causes paralysis.
Here are labs to try.
https://www.mass.gov/service-details/diagnostic-testing-services
University of Massachusetts Amherst Soil and Plant Nutrient Testing Laboratory
203 Paige Laboratory, 161 Holdsworth Way
Amherst, MA...
Your idea is unlikely. Even silkies, if healthy, can fend for themselves. You have an unknown disease moving through your flock and it is time to find out what it is. You need to send or take the next one to die to your state poultry diagnostic lab for a necropsy. IMO, silkies aren't the most...