Hi simbo65
I think you are wise to wait until the weather conditions are a bit better to release BigLeg. Especially if he isn’t desperately trying to escape.
You might want to check out the following https://link.springer.com/article/10.1007/s10344-018-1244-4 but if you don’t want to read it all the conclusion was:
Conclusion
In conclusion, this study is the first to compare overwinter survival and behaviour of wild and rehabilitated hedgehogs and demonstrate that rehabilitated hedgehogs survive well if released in winter and exhibit natural behaviours of nest building, while changes in weight are similar to wild counterparts. Based on these findings, we recommend that wildlife rehabilitators can release rehabilitated hedgehogs during winter if the criteria used for release are similar to those used in this study. That is, hedgehogs should weigh over 600 g, have passed a veterinary health check, are soft-released in areas where the individuals were originally found or suburban areas without main roads and badgers, and during periods of mild weather (> 0 °C) over winter. Following these guidelines will reduce the periods of captivity for rehabilitated hedgehogs and allow them to reintegrate into their natural habitats as soon as possible, improving their welfare, whilst reducing the costs of care for the wildlife rehabilitators.
I got to that via this link from Hedgehog Street https://www.hedgehogstreet.org/guidance-on-releasing-rehabilitated-hedgehogs/
I know it’s slightly different as BigLeg has had an operation, but might be helpful.
