*4.6. Other Bias*

The only other potential source of bias was the non-disclosure of a funding or supporting body, or lack of conflict of interest. Fourteen included studies were at a high risk of bias due to this factor [1,4,8,13,22–24,27,31–35,37]. One study was also considered to be at a high risk of an additional bias, as it was a retrospective review of records from a separately reported, 3 year study [26].

### **5. E**ff**ects of the Interventions**

Seven outcomes arising from the included studies were synthesised using vote counting based on direction of effect. These outcomes were plasma glucose (single/serial sample), plasma corticosterone (single/serial sample), facial corticosterone, bodyweight change (single/serial sample), nest building hemolysis and clotting. A summary of the results of this synthesis is provided in the Summary of Findings table (Table 1). The full analysis and reporting of these outcomes are provided in Supplementary Table S3. Remaining outcomes investigated in the studies are presented narratively below.
