A method for producing a rabbit V L or V H domain that immunospecifically binds to an antigen, wherein said method is a first method comprising: a) selecting from a phage expression library a set of DNA sequences that encode V H or V L domains that immunospecifically bind to said antigen, said phage expression library prepared from DNA or cDNA sequences that encode V H or V L domains and that were obtained from a biological sample of a rabbit containing cells that express immunoglobulins; and b) expressing said set of sequences, or a subset thereof, in bacteria as a fusion protein with CAT, selecting bacteria that have chloramphenicol resistance by virtue of CAT expression, and obtaining sequences encoding rabbit V H or V L domains from the selected bacteria, whereby said bacterial resistance to chloramphenicol conferred by said CAT-fusion correlates with solubility, stability, and/or lack of aggregation of said sequence fused to CAT; or a second method comprising: a) expressing sequences of DNA or cDNA that encode V H or V L domains in bacteria as a fusion protein with CAT, wherein said DNA or cDNA sequences were obtained from a biological sample of a rabbit containing cells that express immunoglobulins; b) selecting bacteria that have chloramphenicol resistance by virtue of CAT expression, and obtaining the set of sequences encoding rabbit V H or V L domains from the selected bacteria, whereby said bacterial resistance to chloramphenicol conferred by said CAT-fusion correlates with solubility, stability, and/or lack of aggregation of said sequence fused to CAT; and c) selecting from a phage expression library DNA sequences that encode V H or V L domains that immunospecifically bind to said antigen, wherein said library is prepared from said set of sequences, or subset thereof. a) selecting from a phage expression library a set of DNA sequences that encode V H or V L domains that immunospecifically bind to said antigen, said phage expression library prepared from DNA or cDNA sequences that encode V H or V L domains and that were obtained from a biological sample of a rabbit containing cells that express immunoglobulins; and b) expressing said set of sequences, or a subset thereof, in bacteria as a fusion protein with CAT, selecting bacteria that have chloramphenicol resistance by virtue of CAT expression, and obtaining sequences encoding rabbit V H or V L domains from the selected bacteria, whereby said bacterial resistance to chloramphenicol conferred by said CAT-fusion correlates with solubility, stability, and/or lack of aggregation of said sequence fused to CAT; a) expressing sequences of DNA or cDNA that encode V H or V L domains in bacteria as a fusion protein with CAT, wherein said DNA or cDNA sequences were obtained from a biological sample of a rabbit containing cells that express immunoglobulins; b) selecting bacteria that have chloramphenicol resistance by virtue of CAT expression, and obtaining the set of sequences encoding rabbit V H or V L domains from the selected bacteria, whereby said bacterial resistance to chloramphenicol conferred by said CAT-fusion correlates with solubility, stability, and/or lack of aggregation of said sequence fused to CAT; and c) selecting from a phage expression library DNA sequences that encode V H or V L domains that immunospecifically bind to said antigen, wherein said library is prepared from said set of sequences, or subset thereof.