In years past, when big clients had big trouble in the workplace, they typically called in their big “full-service” firms for support. But it is increasingly common for such clients to look first to labor and employment boutiques staffed with large firm renegades.

Here in Boston, the employment firm of Ogletree, Deakins, Nash, Smoak & Stewart kicked off 2009 by picking off four well-known lawyers from established Boston firms, and that was just the latest in a string of group defections to labor shops such as Littler Mendelson, Seyfarth Shaw, and Jackson Lewis.

As many full-service firms have focused attention on high margin work in intellectual property, corporate and securities, mergers, finance and “bet the company” litigation, they have neglected other practice areas – such as labor and employment – causing them to wither from their vines. This is curious and potentially threatening when labor and employment issues are growing, and many high margin practice areas that flourished during business growth spurts are contracting.

With 500,000 Americans getting pink slips in the past month alone, there is now boundless demand for lawyers who can handle issues associated with severance packages, reductions in force, salary and benefit reductions, forced vacations, and worker reclassifications.

Furthermore, there is a greater likelihood now more than ever that your biggest clients will face massive litigation assaults in connection with employment matters. Laid off workers often discover wage and hour issues, discrimination issues or other complaints only after they consult a lawyer regarding severance, and then they are likely to refer others who become part of a massive class action. This phenomenon has been evident in recent years with plaintiffs ringing up verdicts of more than $100 million per class against Wal-Mart for missed meal periods, Starbucks for errant tip-pooling, and State Farm for employee misclassifications for wage and hour purposes.

Unfortunately for large employers, 2009 changes in law have only made the employment minefield more treacherous. The Lilly Ledbetter Fair Pay Act has reset the triggers for the running of otherwise restrictive statutes of limitation; the ADA Amendments Act has expanded the definition of workers with disabilities; and federal rules have imposed new I-9 requirements and penalties associated with verification of employee identities and work authorizations. Even those businesses that are faring well have growing needs for immigration practice support as they recruit more globally for talent with special technical or technology training.

For true “full service” firms, there is opportunity in the labor and employment area, not just because human capital is the greatest asset in a knowledge-based economy, but because employment practice is often the gateway to greater intimacy with a client. Human resources professionals often understand the big picture in their organizations better than anyone other than the CEO, and the Vice President of Human Resources is likely to be involved in the recruiting and retention of the General Counsel and other officers in the C-Suite.

The HR pros also understand the value of expert outside counsel because they know that the officers and directors of every company face potential individual liabilities even for seemingly routine employment matters, such as payroll deductions, ERISA or 401k administration, payroll tax returns, or wage and hour violations.

All of these considerations should give leaders at full-service firms pause to think: What really is the value of labor and employment practice for our clients?