Green color on skin under wing

[Upin]

One of our hens was limping badly. We took her to the vet who discovered a bruise on her inner hock - the skin turns green on chickens when they have a bruise, not blue/purple like ours, because their blood chemistry is different. Vet prescribed anti-inflammatories for 5 days and she is doing much better. Her reaction to the injury seemed quite strong for what it ended up being - it must have really really hurt for her to show she was so affected. She’s back in good spirits 3 days later and with better mobility. Vet said Epsom salt baths would be fine bc the heat could help the healing.

how many spoons of Epsom salt should i put in her bath? and for how long should i bath her?