That's my experience with gritty rests. Players turn to chickens.
That's why I invented Gradual Gritty Realism rest rules:
TL

R: They turn essentially long rests into short rests that give back 10-30% of HP and Spell Slots, based on resting conditions.
Long Version:
With Gradual Gritty Realism Resting rules (GGRRr), you give the DM the tools to pace how many ressource a party can regain by regulating resting conditions and giving out Healing and Mana potions so to compensate for more extreme adventuring days.
The GGRRr allow for normal long 6-8 Encounter adventuring days, but also balance around 1-3 Encounters a day.
At low levels (1 to 4) Casters recover spells a little quicker than HP is regenrated, buffing casters a little, but at higher levels casters take longer, debuffing them a little.
Things like "promise no random encounters please" are not necessary anymore, when you can recover some ressources.
Also resting in a town can quicken ressource regeneration to 50 to 100%, because of improved living Conditions, if the qanna spend their monry in Aristocratic living conditions. So the Gradual Gritty Realism Resting rules allow the DM and the players to have flexibility in their resting in contrast to the normal long rest or the Gritty Realism rest, where their is still only 1 optimal strategy (doing it as often as possible).