What are your normal temperatures? If this is within your normal range, or isn't a huge jump from your recent temperatures, they'll most likely be fine. I had birds slightly older than yours by two weeks or so when we got MUCH warmer temperatures (40°C+) and they were fine. I didn't do anything for mine, other than having them in a shaded area with access to water.
Even if there is a sudden rise in temperatures, your birds should be fine. You're doing everything right. Panting is part of cooling off!
Even if there is a sudden rise in temperatures, your birds should be fine. You're doing everything right. Panting is part of cooling off!