Family B-199 in The Immigration of German Colonists to Denmark and Their Subsequent Emigration to Russia in the Years 1759-1766.
Family Rus14-2 in The Immigration of German Colonists to Denmark and Their Subsequent Emigration to Russia in the Years 1759-1766.
Family #73 in the 1775 census.
Johann Balthasar Busch was born in 1720 in the district of Gueglingen, Duchy of Wuerttemberg to an Evangelical Lutheran family. That area of what is now Germany had been ravaged by war and famine for many years, and many of the residents, including the Busch family, were poor farmers with little chance of bettering their lives. Balthasar was concerned providing for his family, as well as to find a way for his children to have better opportunities than he had.
Balthasar was married about 1744-1745 to a woman named Margaretha. Her last name at birth was not recorded in the sources I used, and I could not find it in German Marriage records online. The only possible source does not include her husband's first name nor her last name, and would have them as marrying at the age of 11.
There is another possibility. There is a marriage record for Johann Balthasar and a Anna Margareta Schluechterman in 1722. If our Balthasar's birth year is off by a few years, Johann Balthasar and Anna Margareta Schleuchterman could be his parents. If, for example, he was born in 1725, he could still have married in the late 1730s and had a son, Johannes, born in 1747. I've included the reference for this possibility below, just so we keep track of what has been searched thus far. In a related note, I can't find the name Schleuchterman in any German records. It is almost certainly misspelled, perhaps a variant of Schleuter.
Balthasar and Margareta had four children:
Württemberg, as with much of the southern tier of Germany, had been ravaged by war and famine. Balthasar found it difficult to provide for his family. In 1759, Danish King Frederick V invited Germans from Hessen and the Palantinate to help settle the area of Schleswig-Holstein, at that time under the control of the Danes. The king was interested in converting the marsh lands to arable farm land. Germans were known for their good farming skills and for being hard workers, so it seemed like a win-win situation both both Danes and Germans. Balthasar decided the opportunity to immigrate to Denmark with his family was too attractive to pass up.
He and his family arrived in the Flensburg, the Royal Duchy of Schleswig on 17 July 1761.  They moved to Denmark in November of 1761, living in Colony J3 Friderichsmose in the district of Silkeborg.  They were last recorded living in Denmark in January of 1765. 
The marshlands were very inhospitable to all farmers. Although Germans were known for being hardworking and good farmers with typical farm land, it was far more difficult to convert these former wetlands and grow crops. Most of the German immigrants barely reaped enough to feed their families, let alone to provide food for others in Denmark.
Around that same time, Catherine the Great invited Germans to immigrate to Russia. This offered Heinrich and his family a opportunity for a new, prosperous life. In 1765, Balthasar decided to immigrate with his family to Russia. It is unclear when the family left Denmark for Russia, but they are included on an immigration list of 57 German Danish colonists who traveled to Grimm, Russia.
By the time the family immigrated to Russia, his eldest son Johann married wife Eva Maria, a widow with two daughters. Since they were now considered two families, they are listed separately in the 1775 Grimm Census:
By the time of the 1775 census, the only child still living with Balthasar and his wife was Anna Margaretha, then age 15. This daughter seems to be separate and different from the daughters listed in the immigration records from Denmark. It appears that his youngest daughter was born in Denmark. If any of his other daughters from his first wife were still live, they were married and living in other households.
1775 Grimm Census, Family #73 
1775 Grimm Census, Family #67 
This census listing is for Balthasar's eldest son, Johann, and his family.
Balthasar Busch is not named in the 1798 census, and in all likelihood, he had probably passed away.  Had he survived, he would have been 78 years old.
I checked baptism records of Güglingen for the children, but could not find the name Busch at all.
Possible Source for Balthasar's Parents
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