No. Resonance occurs when the frequency of the object is equal to the frequency of the sound. Resonance amplifies the sound, because the two vibrations are in sync and so are subject to constructive interference, which builds.
The increasing of amplitude (loudness/Db) is what kills, it is the increase in energy. The resonance simply amplifies the sound.
The sound in question is 7 Hz. Therefore, if the natural frequency of chickens is 7 Hz, then it will be subject to resonance. Keep in mind though that the natural frequency of every object is different.
The natural frequency is the frequency of this oscillation, measured in hertz (Hz). This tells you how many oscillations happen per second, which depends on the properties of the spring and the mass of the ball attached to it.
Each chicken will have different mass.
However, on cambridge https://www.cambridge.org/core/journals/animal-science/article/abs/resonant-frequencies-of-broiler-chickens/5C2FD7CB6E0D2E13B19D4C85ECED9D00 which studied the natural frequency of broiler chickens, it says
...vibrating beam technique was used to measure the resonant frequencies of 22 birds which increased in weight from 0·75 to 4·5 kg over 32 days. For a 2-kg bird, the frequencies of 14·6 (s.e. 0·6) Hz when sitting and 3·7 (s.e. 0·8) Hz when standing lie...
This shows that the weight was from 0.75 kg to 4.5 kg, with a 2 kg bird having a frequency of 14.6 +- 0.6 Hz when sitting and 3.7+-0.8 when standing. Therefore, the frequency can even be affected by the position of the chicken.
The energy of sound is also partly dependent on the amplitude or intensity, also known as decibels. Less energy means less lethality; getting hit by an asteroid moving at 10,000 MPH is worse than getting hit by a tennis ball moving at 1,000 MPH because of the energy content (this is simplified, impact mechanics are too lengthy.)
In conclusion, it is possible for a chicken to have a resonance at 7Hz, but it varies so wildly with so many variables that it is unlikely that a frequency of exactly 7Hz would magically resonate with the chicken. The sound (if loud enough) could potentially kill the chicken, but it is not reliable and often times lengthy to calculate.